AMERICAN MANAGEMENT SYSTEMS INC
EXHIBIT 10.7
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<FILENAME>w84788exv10w7.txt
<DESCRIPTION>EXHIBIT 10.7
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                                                                   EXHIBIT 10.7



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                               TABLE OF CONTENTS


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ARTICLE 1 BASIC LEASE INFORMATION AND CERTAIN DEFINITIONS....................1


ARTICLE 2 DEMISE; RENEWAL TERM AND TERM......................................3

      Section 2.01. Demise...................................................3
      Section 2.02. Renewal Terms............................................3
      Section 2.03. Definition of Term.......................................4

ARTICLE 3 DELIVERY OF THE PREMISES TO TENANT; RENTABLE AREA..................4

      Section 3.01. Delivery of the Premises to Tenant.......................4
      Section 3.02. Completion of the Premises...............................5
      Section 3.03. Rentable Area............................................5
      Section 3.04. Allowances Granted to Tenant.............................6

ARTICLE 4 ACCEPTANCE OF THE PREMISES AND BUILDING BY TENANT..................6


ARTICLE 5 BASE RENT..........................................................6

      Section 5.01. Base Rent - Initial Term.................................6
      Section 5.02. Base Rent - Renewal Term.................................7
      Section 5.03. Temporary Rent...........................................8
      Section 5.04. Payment..................................................8
      Section 5.05. Acceptance of Rent.......................................9
      Section 5.06. Survival of Rent Obligation..............................9
      Section 5.07. Default Interest.........................................9

ARTICLE 6 ADDITIONAL RENT....................................................9

      Section 6.01. Operating Expenses.......................................9
      Section 6.02. Real Estate Taxes.......................................15
      Section 6.03. Parking.................................................17
      Section 6.04. Additional Rent Defined.................................17
      Section 6.05. Rent Defined............................................17

ARTICLE 7 SERVICES BY LANDLORD..............................................17

      Section 7.01. Services Generally......................................17
      Section 7.02. Interruption in Services................................17

ARTICLE 8 UTILITIES.........................................................18

      Section 8.01. Computerized Energy Management System...................18
      Section 8.02. Water, Heating, Ventilating and Air Conditioning........19
      Section 8.03. Electricity.............................................19
      Section 8.04. Tenant's Security Regulations...........................20
      Section 8.05. Building Security System................................20

ARTICLE 9 USE...............................................................20
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ARTICLE 10 COMPLIANCE WITH LAWS.............................................20


ARTICLE 11 OBSERVANCE OF BUILDING'S RULES AND REGULATIONS;
HAZARDOUS MATERIALS  .......................................................21

      Section 11.01. Rules and Regulations..................................21
      Section 11.02. Hazardous Materials....................................22

ARTICLE 12 ALTERATIONS......................................................23

      Section 12.01. Approval of Landlord...................................23
      Section 12.02. Ownership of Improvements to Premises..................24

ARTICLE 13 LIENS............................................................24


ARTICLE 14 REPAIRS..........................................................25

      Section 14.01. Tenant's Obligations...................................25
      Section 14.02. Landlord's Obligations.................................25

ARTICLE 15 INSURANCE........................................................26

      Section 15.01. Tenant's Insurance.....................................26
      Section 15.02. Insurance Rating.......................................27
      Section 15.03. Waiver of Subrogation..................................27
      Section 15.04. Landlord Insurance.....................................27
      Section 15.05. Self Insurance and Blanket Insurance...................28

ARTICLE 16 DAMAGE BY FIRE OR OTHER CASUALTY.................................28

      Section 16.01. Termination Rights Due to Damage or Destruction to the
                     Premises...............................................28
      Section 16.02. Damage to the Building.................................29
      Section 16.03. Partial Damage.........................................29
      Section 16.04. Damage During Last Year of Term........................29
      Section 16.05. No Landlord Liability..................................30
      Section 16.06. Apportionment of Rent..................................30

ARTICLE 17 CONDEMNATION.....................................................30

      Section 17.01. Entire Building........................................30
      Section 17.02. Partial Takings Affecting the Premises.................30
      Section 17.03. Termination of Lease...................................31
      Section 17.04. Landlord's Right to Award..............................31

ARTICLE 18 ASSIGNMENT AND SUBLETTING........................................31

      Section 18.01. Permitting Subletting of the Premises..................31
      Section 18.02. Rights of Tenant.......................................32
      Section 18.03. Required Provision in Sublease.........................33
      Section 18.04. Excess Rent............................................33
      Section 18.05. Rights of Landlord.....................................33
      Section 18.06. Permitted Occupants....................................34
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                                       ii

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ARTICLE 19 INDEMNIFICATION..................................................34


ARTICLE 20 SURRENDER OF THE PREMISES........................................35

      Section 20.01. Condition of Premises..................................35
      Section 20.02. Tenant Holdover........................................35

ARTICLE 21 ESTOPPEL CERTIFICATES............................................35


ARTICLE 22 SUBORDINATION AND ATTORNMENT.....................................36

      Section 22.01. Existing Financings....................................36
      Section 22.02. Future Financings......................................36
      Section 22.03. Attornment.............................................37

ARTICLE 23 QUIET ENJOYMENT..................................................37


ARTICLE 24 SIGNS AND FURNISHINGS............................................37

      Section 24.01. Signs and Advertisements...............................37
      Section 24.02. Building Signage.......................................38
      Section 24.03. Furnishings............................................38
      Section 24.04. Satellite Dish.........................................39

ARTICLE 25 DEFAULTS AND REMEDIES............................................39

      Section 25.01. Events of Default......................................39
      Section 25.02. Remedies...............................................40
      Section 25.03. Remedies Cumulative....................................41
      Section 25.04. No Acceptance or Surrender.............................41
      Section 25.05. Customs and Practices..................................41
      Section 25.06. Payment of Tenant's Obligations by Landlord............41
      Section 25.07. Default by Landlord....................................42

ARTICLE 26 SECURITY DEPOSIT.................................................43


ARTICLE 27 INTENTIONALLY OMITTED............................................43


ARTICLE 28 ATTORNEY'S FEES AND LEGAL EXPENSES...............................43


ARTICLE 29 NOTICES..........................................................43


ARTICLE 30 RIGHT OF FIRST REFUSAL...........................................44


ARTICLE 31 MISCELLANEOUS....................................................45

      Section 31.01. No Partnership.........................................45
      Section 31.03. Severability...........................................46
      Section 31.04. Trial by Jury..........................................46
      Section 31.05. Force Majeure..........................................46
      Section 31.06. Captions...............................................46
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      Section 31.07. Benefit and Burden.....................................46
      Section 31.08. No Representations by Landlord.........................46
      Section 31.09. Entire Agreement.......................................46
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                                       iv

<PAGE>



                            OFFICE LEASE AGREEMENT



        THIS OFFICE LEASE AGREEMENT is made and entered into this 12th day of
August, 1993, by and between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia limited
partnership ("Landlord") and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware
corporation ("Tenant"), upon all terms set forth in this Lease and in all
Exhibits hereto, to each and all of which terms Landlord and Tenant hereby
mutually agrees, and in consideration of One Dollar and other valuable
considerations, the receipt and sufficiency of which are hereby acknowledged,
and of the rents, agreements and benefits flowing between the parties hereto, as
follows:


                                  ARTICLE 1
               BASIC LEASE INFORMATION AND CERTAIN DEFINITIONS

        Section 1.01. Each reference to this Lease to information and
definitions contained in Article 1 and each use of the terms capitalized and
defined in this Section 1.01 shall be deemed to refer to, and shall have the
following meanings:

        A.      Building: Hyatt Plaza
                12701 Fair Lakes Circle
                Fairfax, Virginia 22033

        B.      Phase I Space: Refers to approximately 51,262 square feet of
                Rentable Area (defined in Section 3.03 of the Lease) located on
                the seventh (7th) and eighth (8th) floors of the Building, as
                more fully described and shown on Exhibit "A" - Part 1.

        C.      Phase II Space: Refers to approximately 32,974 square feet of
                Rentable Area located on the ninth (9th) and tenth (10th) floors
                of the Building, as more fully described and shown on Exhibit
                "A" - Part 2.

        D.      Phase I Rent Commencement Date: March 1, 1994, subject, however,
                to the provisions of Section 3.01(c) hereof.

        E.      Phase I Rent: Refers to an amount equal to the product obtained
                by multiplying $17.37 by the number of square feet of Rentable
                Area in the Phase I Space.

        F.      Phase II Rent Commencement Date: March 1, 1995, subject,
                however, to the provisions of Section 3.01(d) hereof.

        G.      Phase II Rent: Refers to an amount equal to the product obtained
                by multiplying $17.80 by the number of square feet of Rentable
                Area in the Phase II Space.

        H.      Initial Term: Ten (10) years.

        I.      Commencement Date: March 1, 1994.





<PAGE>

        J.      Expiration Date: February 29, 2004.

        K.      Rentable Area of the Building: 252,395 square feet.

        L.      Base Rent: Refers to the following:

                (i)     From the Phase I Rent Commencement Date to the Phase II
                        Commencement Date the Phase I Rent, any Temporary Rent
                        (defined in Section 5.03) and any Additional Space Rent
                        (defined in Article 30 hereof).

                (ii)    From the Phase II Rent Commencement Date to the
                        expiration of the Term an amount equal to the sum of (1)
                        the Phase I Rent; (2) the Phase II Rent; and (3) any
                        Additional Space Rent.

        M.      Base Year: Refers to the following:

                (i)     During the Initial Term: 1994.

                (ii)    During any Renewal Term: The base year or amount
                        established as part of the Market Rent (as defined in
                        Section 5.02 hereof).

        N.      Base Operating Expenses: The Operating Expenses (defined in
                Section 6.01(b)) incurred by Landlord during the Base Year.

        O.      Base Real Estate Taxes: The Real Estate Taxes (defined in
                Section 6.02(c)) assessed upon the Building during the Base
                Year.

        P.      Tenant's Proportionate Share: The result obtained by multiplying
                100% by a fraction, the numerator being the Rentable Area of the
                Premises and the denominator being the Rentable Area of the
                Building, provided that prior to the Phase II Rent Commencement
                Date the numerator shall be the Rentable Area of the Phase I
                Space only.

        Q.      Landlord's Address for Notices:

                c/o Hazel/Peterson Companies
                12500 Fair Lakes Circle
                Suite 400
                Fairfax, Virginia 22033
                Attention:  Asset Manager




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        R.      Tenant's Address for Notices:

                4050 Legato Road
                Fairfax, Virginia 22030
                Attention:  Thomas W. Huba

        S.      Lease: Collectively refers to this Office Lease Agreement
                together with the following Exhibits which are attached hereto
                and incorporated herein by this reference.


<TABLE>
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                  Exhibits

                  <S>        <C>
                  "A"        Floor Plans
                  "B"        Leasehold Improvements
                  "C"        Modified Method
                  "D"        Cleaning Specifications
                  "E"        HVAC Specifications
                  "F"        Barrier Removal Program
                  "G"        Rules and Regulations
                  "H"        Form Subordination Agreement
</TABLE>

        T.      Broker: Cushman & Wakefield of Virginia and Grubb & Ellis

        U.      Premises: Refers to the Rentable Area demised to Tenant by this
                Lease.

        V.      Fair Lakes: A mixed-use development in Fairfax County, Virginia.


                                  ARTICLE 2
                        DEMISE; RENEWAL TERM AND TERM

        Section 2.01. Demise. Landlord leases to Tenant, and Tenant leases from
Landlord, the Premises located in the Building for the Term (defined in Section
2.03) and subject to the provisions hereof. The Initial Term of this Lease shall
be for the period specified in Section 1.01 and shall begin at midnight on the
Commencement Date and shall, unless this Lease is sooner terminated in
accordance with the provisions of this Lease, end at midnight on the Expiration
Date, provided, however, that if for any reason the Expiration Date shall be a
day other than the final day of a calendar month then, the Term of this Lease
shall be extended so that it will expire on the last day of the calendar month
in which the Expiration Date takes place.

        Section 2.02. Renewal Terms. Tenant shall have the right to renew and
extend the Term of this Lease for two (2) Renewal Terms (herein so called) of
five (5) years each upon and subject to the following terms and conditions:

        (a)     Tenant may exercise its right to a Renewal Term by giving
written notice thereof to Landlord no later than thirty (30) days after its
receipt of the Market Rent Notice (as defined in Section 5.02 hereof) for the
Renewal Term in question. The Renewal Term shall commence immediately upon the
expiration of the Initial Term (as extended if Tenant had previously exer-



                                      -3-
<PAGE>

cised its right to the first Renewal Term) and upon such exercise the
"Expiration Date" of the Term shall automatically become the last day of the
current Renewal Term.

        (b)     The exercise by Tenant of its right to a Renewal Term must be
made, if at all, by written notice executed by Tenant and delivered to Landlord
on or before the date set forth hereinabove. Once Tenant has exercised its
option to a Renewal Term, the exercise may be revoked as more particularly
described in Section 5.02(b) hereof. Tenant shall not have the right to a
Renewal Term if Tenant is in Default (as defined in Section 25.01 hereof) under
this Lease, either at the time Tenant gives notice of its election, or
immediately prior to the commencement of a Renewal Term. If Tenant does not
exercise its right to a Renewal Term in a timely manner, then Tenant's rights
with respect thereto shall expire and be of no force or effect.

        Section 2.03. Definition of Term. As used in this Lease the word "Term"
collectively refers to the Initial Term, Renewal Term, if any, and, any
Temporary Occupancy Period (hereinafter defined).


                                  ARTICLE 3
              DELIVERY OF THE PREMISES TO TENANT; RENTABLE AREA

        Section 3.01. Delivery of the Premises to Tenant.

        (a)     Landlord shall deliver the Phase I Space and Phase II Space to
Tenant in its "as is" and "where as" condition with only the improvements
identified on Schedule 1 of Exhibit "B" hereto (the "Existing Improvements") on
or before December 5, 1993. For every day beyond December 5, 1993 that Landlord
has not delivered the Premises, the Rent Commencement Date for Phase I and Phase
II will be extended by one (1) day. The provisions of Exhibit "B" hereto shall
govern the construction and installation of all Leasehold Improvements (as
defined in Exhibit "B").

        (b)     It is acknowledged and agreed that Tenant (and its agents,
contractors and employees) may enter upon the Premises commencing after the date
it is delivered to Tenant pursuant to subparagraph (a) hereof to perform the
construction work required by this Lease to be performed by Tenant. Any entry
prior to the Commencement Date shall be subject to all of the terms and
conditions of this Lease, however, Tenant's obligations to pay Rent hereunder
shall commence on the Phase I Rent Commencement Date with respect to the Phase I
Space and on the Phase II Rent Commencement Date with respect to the Phase II
Space.

        (c)     The Phase I Rent Commencement Date shall occur on the earlier
of (i) March 1, 1994 or (ii) the date on which Tenant occupies any portion of
the Phase I Space for the operation of its normal business, provided, however,
that if Tenant occupies only a portion of the Phase I Space prior to March 1,
1994, then the Rent payable with respect to the Phase I Space for the period
from Tenant's occupancy for its normal business operations until March 1, 1994
shall be prorated so that Tenant shall pay Rent only with respect to the portion
of the Phase I Space Tenant is occupying for its normal business operations,
provided further, however, that Tenant shall commence paying Rent with respect
to all of the Phase I Space on March 1, 1994 whether or not Tenant has occupied
all of the Phase I Space. The period from Tenant's occupancy of any por-



                                      -4-
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tion of the Phase I Space for its normal business operations until March 1, 1994
is hereinafter referred to as the "Temporary Occupancy Period". The Tenant's
occupancy of any Phase I Space during the Temporary Occupancy Period will be
subject to the terms and conditions of this Lease and Tenant will be obligated
to pay Temporary Rent with respect to such space computed in accordance with
Section 5.03 hereof.

        (d)     The Phase II Rent Commencement date shall occur on the earlier
of (i) March 1, 1995 or (ii) the date on which Tenant occupies any portion of
the Phase II Space for the operation of its normal business, provided, however,
that if Tenant occupies only a portion of the Phase II Space prior to March 1,
1995, then the Rent payable with respect to the Phase II Space for the period
from Tenant's occupancy for its normal business operations until March 1, 1995
shall be prorated so that Tenant shall pay Rent only with respect to that
portion of the Phase II Space Tenant is occupying for its normal business
operations, provided, further, however, that Tenant shall commence paying Rent
with respect to all of the Phase II Space on March 1, 1995 whether or not Tenant
has occupied all of the Phase II Space. The period from Tenant's occupancy of
any portion of the Phase II Space for its normal business operations until March
1, 1995 is hereinafter referred to as the "Temporary Occupancy Period". Tenant's
occupancy of any Phase II Space during the Temporary Occupancy Period will be
subject to the terms and conditions of this Lease and Tenant will be obligated
to pay Temporary Rent computed in accordance with Section 5.03 hereof.

        (e)     Tenant shall indemnify Landlord and hold Landlord harmless from
and against any and all claims, damages, losses, liabilities, costs and expenses
(including without limitation attorneys' fees and court costs) which Landlord
may incur as a result of Tenant's entry on the Premises and construction of the
Leasehold Improvements to the Premises.

        Section 3.02. Completion of the Premises. Upon completion of a phase of
the Premises, Tenant will supply Landlord with (i) a certificate from the
Tenant's Architect (defined in Exhibit "B"), that, in its professional judgment,
the Leasehold Improvements to be constructed in the phase have been
substantially completed, and (2) copies of the non-residential use permit for
the phase.

        Section 3.03. Rentable Area. The term "Rentable Area" as used herein
means all the floor area in the Building and/or in the Premises and has been
calculated using a modified version of the standard method of measurements of
the Washington D.C. Association of Realtors (formerly the Washington Board of
Realtors) a copy of which is attached hereto as Exhibit "C" (the "Modified
Method"). The Rentable Area of each phase of the Premises is approximately
stated in Section 1.01 and shall be specifically calculated by Landlord's
architect using the Modified Method as Approved Plans (defined in Exhibit "B")
for a phase are completed. Upon such determination: (i) Landlord's architect
will send written certification of such determination to Landlord and Tenant
showing the method of calculation; (ii) such calculations shall be subject to
confirmation by Tenant's Architect and (iii) once the Rentable Area is agreed
upon the Rentable Area of the Premises and Base Rent specified in Section 1.01
shall be appropriately adjusted, if necessary, to reflect the agreed upon number
of square feet of Rentable Area of the Premises. The Rentable Area of the
Building and the Premises shall be adjusted, if necessary, by


                                      -5-
<PAGE>

Landlord's architect using the Modified Method in the event of any future
expansion or modification of the Premises. If the number of square feet of the
Rentable Area of the Premises changes, then Tenant's Proportionate Share shall
be adjusted effective as of the date of any such change.

        Section 3.04. Allowances Granted to Tenant. Landlord grants to Tenant an
allowance (the "Tenant's Allowance") equal to $10.00 per square foot of Rentable
Area in the original Premises. The Tenant Allowance will be disbursed pursuant
to the provisions of Exhibit "B". Any undisbursed or unused portion of the
Tenant Allowance may be used by Tenant to apply towards moving expenses or Rent
accruing hereunder at such time as all of the fees, costs and expenses
associated with work which Tenant is required to pay under this Lease have been
paid in full.


                                  ARTICLE 4
              ACCEPTANCE OF THE PREMISES AND BUILDING BY TENANT


        Taking possession of a phase of the Premises by Tenant shall be
conclusive evidence that Tenant: (i) accepts such phase as suitable for the
purposes for which they are leased; (ii) waives any defects in the phase of the
Premises. Except as specifically set forth in this Lease, and except for
negligence or willful misconduct of Landlord, its agents, employees, licensees
or servants, Landlord shall not be liable to Tenant or any of its agents,
employees, licensees, servants, or invitees for any injury or damage to person
or property due to (i) the condition or design of or any defect in the Premises
or its mechanical, plumbing and electrical systems and equipment which may exist
or occur, or (ii) any work performed by Tenant, its agents, employees,
licensees, servants, and invitees, and Tenant expressly assumes all risks for
injury or damage to person or property, either proximate or remote, resulting
from the condition of the Premises.


                                  ARTICLE 5
                                  BASE RENT

        Section 5.01. Base Rent - Initial Term. Commencing on the Rent
Commencement Date and continuing thereafter during the Initial Term of this
Lease Tenant shall pay to Landlord monthly, in lawful money of the United
States, without demand or offset (other than specifically permitted herein);
Base Rent as specified in Section 1.01 hereof. The Base Rent shall be paid in
equal monthly installments, each payable in advance, on or before the first day
of each calendar month during the Term. The monthly installment of Base Rent for
any partial calendar month of the Term shall be appropriately prorated.
(References to Base Rent in this Lease collectively refer to the Initial Term -
Base Rent and the Renewal Term - Base Rent determined in accordance with Section
5.02 hereof).

        Section 5.02. Base Rent - Renewal Term. In the event Tenant has
exercised an option for a Renewal Term of this Lease, then Tenant shall pay to
Landlord, during a Renewal Term, a Base Rent equal to ninety-five percent (95%)
of the then market rate being charged and/or granted to a tenant seeking a five
(5) year lease for a space of a size comparable to the Rentable Area of the
Premises, in a full service, first class office building located in the Fairfax
Center


                                      -6-
<PAGE>

area in buildings that are similar in age, quality of construction and
management of the Building (the "Market Rent"), multiplied by the number of
square feet of Rentable Area in the Premises. In determining Market Rent,
Landlord and Tenant shall also establish a new base (whether a year or an
amount) reflective of the market which will be used to determine the Base
Operating Expenses and Base Real Estate Taxes for the Renewal Term. All
determinations of Market Rent shall (i) reflect market conditions expected to
exist as of the date Base Rent based on Market Rent is to commence (including
base rents and escalations, rental abatements, construction allowances and other
tenant concessions, operating expense and tax passthrough provisions, and other
terms expected to be agreed to in market leases entered into at such time); (ii)
reflect the fact that Landlord is providing Tenant parking free of charge
pursuant to Section 6.03 hereof; and (iii) reflect any rent premiums that
buildings in Fair Lakes may receive. In determining the Market Rent, Landlord
and Tenant shall employ the following method and timetable to establish the
Market Rent.

        (a)     Not later than fourteen (14) months prior to the expiration date
of the Initial Term (or the first Renewal Term if Tenant had previously
exercised its option for a Renewal Term), Landlord shall deliver to Tenant
written notice (the "Market Rent Notice") of its proposed Market Rent for the
Premises during the applicable Renewal Term based on Landlord's determination of
the Market Rent. If Tenant (within the time period permitted by and in the
manner required by Section 2.02(a) hereof) elects to exercise its right to a
Renewal Term, Tenant shall also notify Landlord of Tenant's election to either
accept or reject the proposed Market Rent, set forth in the most recent Market
Rent Notice. Should Tenant accept the Market Rent proposed by Landlord in the
most recent Market Rent Notice, then such Market Rent will be used during the
applicable Renewal Term;

        (b)     Should Tenant reject the Market Rent set forth in the most
recent Market Rent Notice, Landlord and Tenant for _ period of thirty (30) days
will attempt to negotiate _ Market Rent. Should the parties reach an agreement,
then the agreed upon Market Rent shall be used during the applicable Renewal
Term. Should the parties fail to reach an agreement within such period, then,
Tenant, by written notice to Landlord given within ten (10) days after the
expiration of the foregoing thirty (30) day period, shall have the option to
either U) rescind its election for the Renewal Term, in which case, this Lease
shall terminate on the Expiration Date, or (ii) elect to use the appraiser
method described in subparagraph (c) hereof. An election by Tenant will be
irrevocable. A failure to notify Landlord within the ten (10) day period will be
deemed to be Tenant's election to rescind its election for the Renewal Term.

        (c)     In the event Tenant elects pursuant to subparagraph (b)(ii) to
invoke the appraiser method, Tenant in its notice to Landlord will select a
broker who has at least ten (10) years experience leasing commercial office
space in Fairfax County, Virginia (a "Broker"), to determine a Market Rent.

                (i)     Within ten (10) days after its receipt of the Tenant's
                        notice, Landlord shall engage a Broker and shall notify
                        the Tenant thereof. In the event Landlord does not
                        engage a Broker and provide Tenant notice as required
                        above,


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<PAGE>

                        then the Tenant's Broker shall select a Market
                        Rent which shall be deemed the Market Rent used during
                        the applicable Renewal Term.

                (ii)    Within five (5) days after the selection by Landlord
                        of a Broker, the two (2) Brokers shall (a) each
                        render their own determination of the Market Rent and
                        (b) choose a third Broker and notify Landlord and
                        Tenant of said choice. Each party shall bear the cost
                        of its appointed Broker and shall share equally the
                        cost of the third Broker. In the event that said two
                        (2) Brokers cannot agree on the choice of a third
                        Broker and they notify the parties thereof, then the
                        President of the Fairfax County Board of Realtors shall
                        choose a third Broker.

                (iii)   Within fifteen (15) days after the selection of the
                        third Broker, the third Broker shall, by
                        written notice, notify Landlord and Tenant of its
                        determination of Market Rent. The Market Rent for
                        purposes of this section shall equal the average of the
                        two closest determinations; provided, however, that (a)
                        if any one determination is agreed upon by any two of
                        the Brokers, then the Market Rent shall be such
                        determination, and (b) if any one determination is
                        equidistant from the other two determinations, then the
                        Market Rent shall be such middle determination.

        Section 5.03. Temporary Rent. During any Temporary Occupancy Period,
Tenant shall be obligated to pay to Landlord an adjusted rent (the "Temporary
Rent") for the Rentable Area occupied by Tenant computed in accordance with this
Section. For any Phase I Space occupied by Tenant during a Temporary Occupancy
Period, then Temporary Rent will be an amount equal to $7.00 per square foot of
Rentable Area occupied by Tenant. For any Phase II Space occupied by Tenant
during a Temporary Occupancy Period, the Temporary Rent will be $11.87 per
square foot of Rentable Area occupied by Tenant. The Temporary Rent shall be
paid in the same manner as Base Rent.

        Section 5.04. Payment. All Rent (as hereinafter defined) shall be paid
to Landlord by Tenant when due at Landlord's Address for Notices as specified in
Section 1.01, or such other place as Landlord may from time to time designate in
writing.


        Tenant shall only be required to pay Rent to one entity or person. In
the event more than one entity or person shall constitute Landlord hereunder,
they shall appoint by written notice to Tenant a single entity or person, (who
may be one of the entities or persons constituting Landlord), as (i) the
designated recipient of Rent; and (ii) the representative to whom Tenant should
direct all notices to Landlord and upon whose actions the Tenant may rely.
Tenant shall be entitled to pay Rent and rely upon the last named single
recipient until a new single recipient is named by written notice to Tenant.

        Section 5.05. Acceptance of Rent. If Landlord shall direct Tenant to pay
Rent to a lockbox or other depository whereby checks issued in payment of Rent
is initially cashed or deposited by a person or entity other than Landlord
(albeit on Landlord's authority), then, for any and all purposes under this
Lease: (i) Landlord shall not be deemed to have accepted such payment


                                      -8-
<PAGE>

until ten (10) days after the date on which Landlord shall have actually
received such funds, and (ii) Landlord shall be deemed to have accepted such
payment if (and only if) within said ten (10) day period, Landlord shall not
have refunded (or attempted to refund) such payment to Tenant. Nothing contained
in the immediately preceding sentence shall be construed to place Tenant in
default of Tenant's obligation to pay Rent if and for so long as Tenant shall
timely pay the Rent required pursuant to this Lease in the manner designated by
Landlord.

        Section 5.06. Survival of Rent Obligation. The obligation of Tenant with
respect to the payment of past due Rent shall survive the termination of this
Lease.

        Section 5.07. Default Interest. In the event any installment of Rent due
hereunder is not paid within five (5) calendar days after it is due, then such
delinquent installment of Rent or any component thereof shall bear interest from
the date originally due until paid, at the Default Rate (hereinafter defined in
Section 25.06 hereof). Notwithstanding the foregoing, Landlord agrees to waive
imposition of such interest with respect to the first late payment in any
calendar year.


                                  ARTICLE 6
                               ADDITIONAL RENT

        Section 6.01. Operating Expenses.

        (a)     Commencing on (i) January 1, 1995 with respect to the Phase I
Space and (ii) the Phase II Rent Commencement Date with respect to the Phase II
Space, and thereafter, throughout the Term, Tenant shall pay on a monthly basis,
without demand, as Additional Rent for the Premises, Tenant's Proportionate
Share of the amount by which Operating Expenses (as defined in Section 6.01(b)
hereof) exceed the Base Operating Expenses. Such payments shall be made as
follows:

        (i)     Commencing on January 1, 1995 and on the first day of January of
                each year during the remainder of the Term or as soon thereafter
                as is practicable, Landlord shall furnish Tenant with Landlord's
                reasonable estimate of the Operating Expenses for the year. On
                the first day of each month during such year, Tenant shall pay
                1/12th of Tenant's Proportionate Share of the difference between
                the estimated Operating Expenses for such year and the Base
                Operating Expenses. If for any reason Landlord has not provided
                Tenant with Landlord's Operating Expenses estimate on or before
                the first day of January of any year during the Term (or by the
                Commencement Date, as the case may be), then, until the first
                day of the calendar month following the month in which Tenant is
                given Landlord's estimate of Operating Expenses, Tenant shall
                continue to pay Landlord on the first day of each calendar month
                the monthly sum payable by Tenant under this Section 6.01 for
                the month of December of the preceding year.

        (ii)    On March 1, 1996 and thereafter on the first day of March of
                each year during the remainder of the Term, or as soon
                thereafter as reasonably practical, Landlord shall furnish to
                Tenant a statement of the actual Operating Expenses for the
                preceding year. Such statement shall provide Tenant with
                reasonable details regard-


                                      -9-
<PAGE>

                ing the various components of Operating Expenses. Within thirty
                (30) days after the delivery of that statement, Tenant shall
                either (i) notify Landlord, in writing, the Tenant objects to a
                component of the Operating Expenses on the grounds that it is
                not permitted by Section 6.01 hereof or (ii) pay to Landlord a
                lump sum payment equal to the amount, if any, by which Tenant's
                Proportionate Share of the actual Operating Expenses exceeds the
                amount, if any, which Tenant has paid toward the estimated
                operating Expenses pursuant to Section 6.01(a)(i) above or the
                undisputed amount thereof. Should Tenant dispute an Operating
                Expenses statement, (i) Tenant and Landlord shall in good faith
                attempt to resolve such dispute and (ii) in the event Landlord
                is unable to demonstrate by invoices or other supporting
                information the inclusion of an item or expenses as an Operating
                Expense, Landlord will not be permitted to charge or include
                such item. Within thirty (30) days after resolution of the
                dispute, Tenant will make a lump sum payment equal to the amount
                agreed upon by Landlord and Tenant. if Tenant's Proportionate
                Share of the actual operating Expenses is less than the amount
                Tenant has paid toward the estimated Operating Expenses pursuant
                to Section 6.01(a)(1) above, Landlord shall either (i) apply
                such amount to the next accruing installments of Rent due
                hereunder or (ii) if such excess arises after the Expiration
                Date, refund such amount to Tenant provided no Default by Tenant
                exists under Sections 25.01(a) and (b) hereof. The effect of
                this Section 6.01(a)(ii) is that Tenant will pay during each
                year during the Term Tenant's Proportionate Share of the actual
                operating Expense in excess of the Base Operating Expenses.

        (iii)   If the Term ends on a date other than the last day of December,
                the actual Operating Expenses for the year in which the
                Expiration Date occurs shall be prorated so that Tenant shall
                pay that portion of Tenant's Proportionate Share of Operating
                Expenses for such year represented by a fraction, the numerator
                of which shall be the number of days during such fractional year
                falling within the Term, and the denominator of which is 365 (or
                366, in the case of a leap year). The provisions of this Section
                6.01 shall survive the Expiration Date or any sooner termination
                provided for in this Lease.

        (iv)    Tenant shall have the right, during business hours and upon
                reasonable prior notice, one time during each calendar year to
                inspect Landlord's books and records relating to Operating
                Expenses, and/or to have such books and records audited at
                Tenant's expense by a certified public accountant mutually
                designated by Landlord and Tenant, except that any audit that
                discloses a discrepancy of more than three percent (3%) in the
                annual Operating Expenses and/or Real Estate Taxes shall be at
                Landlord's expense. Any discrepancy shall be promptly corrected
                by a payment of any shortfall to Landlord by Tenant within
                thirty (30) days after the applicable audit, or by a credit
                against the next payment(s) of rent hereunder, as may be
                applicable. In the event Tenant does not contest a statement of
                Operating Expenses within three hundred sixty-five (365) days
                after it is rendered, such statement shall become binding and
                conclusive; provided, however, that if a timely audit of
                Operating Expenses for a particular year reveals an error
                resulting




                                      -10-
<PAGE>

                in any overcharge with regard to particular expenses in such
                year, Tenant shall thereupon have the right to reexamine
                Landlord's books and records with respect to the immediately
                preceding two (2) calendar years for the sole purpose of
                determining whether the same error resulting in an overcharge
                with respect to the same expenses in such immediately preceding
                two (2) calendar years, and if so Tenant shall be entitled to a
                refund of such overcharged amount.

        (b)     As used in this Lease, "Operating Expenses" means all expenses,
costs, and disbursements of every kind which Landlord incurs, pays or becomes
obligated to pay in connection with the ownership, operation, repair, and
maintenance of the Building, which costs shall include all expenditures by
Landlord to maintain all facilities in operation at the beginning of the Term
and such additional facilities installed in subsequent years as Landlord may
consider necessary or beneficial for the operation of the Building. All
Operating Expenses shall be determined according to generally accepted
accounting principles (which shall be consistently applied) and shall include,
but are not limited to, the following:

        (i)     Wages, salaries, and fees of all personnel or entities
                (exclusive of Landlord's executive personnel) engaged in the
                operation, repair, maintenance, or security of the Building,
                including taxes, insurance, and benefits relating thereto (in
                the event the personnel service more than one building, expenses
                related to such person will be pro-rated to the Building on the
                basis of the amount of time the personnel spent servicing the
                Building);

        (ii)    All supplies and materials used in the operation, repair,
                security, and maintenance of the Building.

        (iii)   Cost of all maintenance and service agreements for the Building
                and the equipment therein, including, without limitation, alarm
                service, water treatment services, janitorial services, security
                systems service, window cleaning, service on electrical and
                mechanical components, trash removal, elevator maintenance,
                extermination service, plumbing service, grounds keeping, and
                landscaping;

        (iv)    Cost of all insurance relating to the Building for which
                Landlord is responsible hereunder (exclusive, however, of
                payments made by tenants of the Building pursuant to provisions
                in their lease similar to Section 15.02 hereof), or which
                Landlord considers reasonably necessary for the operation of the
                Building, including, without limitation, the cost of property,
                casualty and liability insurance applicable to the Building and
                Landlord's personal property used in connection therewith, and
                the cost of business interruption or rental insurance in such
                amounts as will reimburse Landlord for all losses of earnings
                and other income attributable to such perils as are commonly
                insured against by prudent landlords or required by Landlord's
                lender;

        (v)     Cost of repairs and maintenance (excluding repairs and
                maintenance paid by proceeds of insurance or by Tenant or other
                third parties or paid under guaranties, warranties or service
                contracts more particularly described in subparagraph (iii)


                                      -11-
<PAGE>

                hereof, and alterations attributable solely to tenants of the
                Building other than Tenant) of the Building;

        (vi)    All utility costs of the Building (exclusive, however, of such
                special utility services as are provided for in Article 8
                hereof, the costs of which special utility services shall be
                payable as therein provided), including, without limitation,
                water, power, fuel, heating, lighting, air-conditioning, and
                ventilating;

        (vii)   Amortization of the cost of installation of capital investment
                items which are installed primarily to reduce operating costs
                for the general benefit of the Building's tenants or to enhance
                the efficient operation of Building or which may be required in
                the future by any governmental authority, but which shall not
                include capital investment items required or generated by any
                specific tenant use. All such costs, including interest costs,
                shall be amortized over the reasonable life of the capital
                investment items, with reasonable life and amortization schedule
                being determined by Landlord according to generally accepted
                accounting principles, but in no event to extend beyond the
                reasonable life of the Building;

        (viii)  Landlord's central accounting costs, annual audits (except those
                costs and audits incurred for Landlord's sole benefit), and
                legal fees relating to the operation of the Building, but
                excluding legal fees relating to specific tenants;

        (ix)    A management fee to the manager of the Building, which fee shall
                not exceed the normal and customary management fees charged for
                managing comparable buildings in Fairfax County, Virginia.

        (x)     The Building's pro-rata share of office rent or rental value for
                any central Building management office located in another
                building located within Fair Lakes, provided that such rent or
                rental value shall not increase by more than two percent (2%) in
                any calendar year;

        (xi)    The Fair Lakes League Assessment, provided, however, that such
                assessment shall be included in Operating Expenses only if and
                to the extent that the item or service to which the assessment
                relates would be properly includible in Operating Expenses
                pursuant to this Section 6.01(b) if such item or service was
                provided or performed directly by Landlord; and

        (xii)   Costs to implement and maintain any controls on access to the
                Building parking lot which Landlord deems necessary pursuant to
                Section 6.03 hereof.

        (c)     Notwithstanding any other provision of this Lease, operating
Expenses (as defined in Section 6.01(b) above) shall not include; and Landlord
shall be solely liable for, the following expenses:

        (i)     Costs of a capital nature (other than those permitted by Section
                6.01(b)(7) above), including but not limited to, capital
                improvements, capital repairs; capital equip-



                                      -12-
<PAGE>

                ment and capital tools, all in accordance with generally
                accepted accounting principles;

        (ii)    Repairs or other work occasioned by insured casualty or by the
                exercise of eminent domain, to the extent Landlord is
                reimbursed by insurance maintained by Landlord or by Tenant or
                another tenant of the Building or by the condemning authority;

        (iii)   Leasing commissions, attorneys' fees, costs and disbursements
                and other expenses incurred in connection with negotiations or
                disputes with present or prospective tenants or other occupants
                of the Building;

        (iv)    Costs incurred in improving, decorating, building-out, painting
                or redecorating space for other tenants of the Building;

        (v)     Expenses in connection with services or other benefits of a type
                which are not provided Tenant but which are provided to another
                tenant of the Building;

        (vi)    Costs incurred due to violation by Landlord or any other tenant
                of the Building of the terms and conditions of any lease of
                space in the Building;

        (vii)   Interest or debt or amortization payments on any mortgage or
                mortgages;

        (viii)  Payments of rent by Landlord to any ground lessor;

        (ix)    Landlord's general overhead not related to the operation of the
                Building (but without limiting Landlord's right to seek
                reimbursement as provided in Sections 6.01(b)(i), (viii), (ix)
                and (x) above);

        (x)     Advertising and promotional expenditures with respect to the
                Building;

        (xi)    Any costs, fines or penalties incurred due to either (i)
                violations by Landlord of any governmental rule or authority or
                (ii) late payments by Landlord under any service, contract, lien
                or encumbrance applicable to the Building;

        (xii)   Wages, salaries or other compensation paid to any executive
                employees above the grade of building manager;

        (xiii)  Rentals and other related expenses incurred in leasing
                air-conditioning systems, elevators or other equipment
                ordinarily considered to be of capital nature;

        (xiv)   Any cost or expense whatsoever arising from or related to any
                clean-up of any Hazardous Materials (as defined in Section
                11.02(d)), or any governmental penalty of fines associated
                therewith, excepting, however, any such cost or expense
                resulting from the negligent or intentional acts of Tenant;



                                      -13-
<PAGE>

        (xv)    The cost of excessive use of Building utilities (such as HVAC or
                electricity) by other tenants of the Building, and/or utility
                service by other tenants outside normal Building hours, and/or
                utility service paid by tenants directly to utility companies
                based on separate metering;

        (xvi)   Any other cost or expense which would not be considered an
                operating expense under generally accepted accounting principles
                consistently applied;

        (xvii)  Costs incurred in connection with the sale, financing,
                refinancing, mortgaging or change of ownership of the Building
                or the Project, including without limitation, brokerage
                commissions, attorneys' and accountants' fees, closing costs,
                title insurance premiums, transfer taxes and interest charges;

        (xviii) Any and all loss, claim, damage, award or other amount paid or
                payable by Landlord (including all attorneys, fees, court costs
                and other costs incurred in connection therewith) as a result or
                arising out of any act of negligence, breach of contract or
                willful misconduct by the Landlord or its agents, employees or
                contractors to the extent not covered by insurance;

        (xix)   Bad debt losses, rent losses or reserves for such losses;

        (xx)    Non-cash items, such as deductions for depreciation and
                amortization of the Building and the Building equipment;

        (xxi)   Costs incurred in operating concessions such as (but not limited
                to) newspaper or cigarette stands;

        (xxii)  Any cost representing an amount paid for services or materials
                to a person, firm or entity related to Landlord or any general
                partner of Landlord to the extent such amount exceeds the amount
                that would be paid for such services or materials at the then
                existing market rates to an unrelated person, firm or
                corporation; and

        (xxiii) Any capital costs associated with phasing out chlorofluorocarbon
                refrigerants.

        (d)     If the average occupancy rate for the Building during any
calendar year (including the Base Year), is less than one hundred percent
(100%), or if any tenant is separately paying for utility or janitorial services
furnished to its premises which normally would be included in Operating Expenses
(as opposed to janitorial or utility services addressed in Section 6.01(c)(5)
and (15) and/or special utility services as are provided in Article 8 hereof),
then Operating Expenses for such calendar year shall be deemed to include all
additional expenses, as reasonably estimated by Landlord, which would have been
incurred during such calendar year if such average occupancy rate had been one
hundred percent (100%) and if Landlord paid for utility and janitorial services
furnished to such premises.


                                      -14-
<PAGE>

        Section 6.02. Real Estate Taxes.

        (a)     Commencing on (i) January 1, 1995 with respect to the Phase I
Space and (ii) the Phase II Rent Commencement Date with respect to the Phase II
Space, and continuing thereafter throughout the Term, Tenant shall pay on a
monthly basis, without demand, as Additional Rent for the Premises, Tenant's
Proportionate Share of the amount by which Real Estate Taxes (as defined in
Section 6.02(c) hereof) exceed the Base Real Estate Taxes. Such payments shall
be made as follows:

        (i)     Prior to January 1, 1995 and on the first day of January of each
                year during the remainder of the Term, or as soon thereafter as
                practicable, Landlord shall furnish Tenant with Landlord's
                reasonable estimate of the Real Estate Taxes for the forthcoming
                year. On the first day of each month during such year, Tenant
                shall pay 1/12th of Tenant's Proportionate Share of the
                difference, if any, between the estimated Real Estate Taxes for
                such year and the Base Real Estate Taxes. if for any reason
                Landlord has not provided Tenant with Landlord's estimate of
                Real Estate Taxes on or before the first day of January of any
                year during the Term, then until the first day of the calendar
                month following the month in which Tenant is given Landlord's
                estimate of Real Estate Taxes, Tenant shall continue to pay to
                Landlord on the first day each calendar month the monthly sum
                payable by Tenant under this Section 6.02 for the month of
                December of the preceding year.

        (ii)    Commencing on March 1, 1996 and thereafter on the first day of
                March of each year during the remainder of the Term, or as soon
                thereafter as reasonably practical, Landlord shall furnish to
                Tenant a statement of the actual Real Estate Taxes for the
                preceding year. Within thirty (30) days after the delivery of
                that statement, a lump sum payment will be made by Tenant equal
                to the amount, if any, by which Tenant's Proportionate Share of
                the actual Real Estate Taxes exceeds the amount, if any, which
                Tenant has paid toward the estimated Real Estate Taxes pursuant
                to Section 6.02(a)(i) above. If Tenant's Proportionate Share of
                such items is less than the amount Tenant has paid toward the
                estimated Real Estate Taxes pursuant to Section 6.02(a)(i)
                above, Landlord shall apply such amount to the next accruing
                installments of Rent due hereunder. The foregoing
                notwithstanding, Landlord shall have the right from time to time
                during any year, but not more frequently then twice during any
                calendar year, to notify Tenant in writing of any change in
                Landlord's estimate of Real Estate Taxes for the then current
                year, in which event Tenant's Proportionate Share of Real Estate
                Taxes, as previously estimated, shall be adjusted to reflect the
                amount shown in such notice and shall be effective, and due from
                Tenant, on the first day of each month following Landlord's
                giving of such notice. The effect of this Section 6.02(a) is
                that Tenant will pay during each year during the Term Tenant's
                Proportionate Share of the actual Real Estate Taxes in excess of
                the Base Real Estate Taxes.

        (b)     If the Term ends on a date other than the last day of December,
the actual Real Estate Taxes for the year in which the Expiration Date occurs
shall be prorated so that Tenant




                                      -15-
<PAGE>

shall pay that portion of Tenant's Proportionate Share of Real Estate Taxes for
such year represented by a fraction, the numerator of which shall be the number
of days during such fractional year falling within the Term, and the denominator
of which is 365 (or 366, in the case of a leap year). The provisions of this
Section 6.02 shall survive the Expiration Date or any sooner termination
provided for in this Lease.

        (c)     As used in this Lease, the term "Real Estate Taxes" shall
                include the following:

        (i)     All real estate taxes, including general and special
                assessments, if any, which are imposed upon Landlord or assessed
                against the Building or the land upon which the Building is
                situated;

        (ii)    Any other present or future taxes or governmental charges that
                are imposed upon Landlord, or assessed against the Building or
                the land upon which the Building is situated, including, but not
                limited to, any tax levied on or measured by the rents payable
                by tenants of the Building which is in the nature of, or in
                substitution for, real estate taxes. Any inheritance, estate,
                gift, franchise, corporation, income, or net profits tax which
                may be assessed against Landlord and/or the Building shall be
                excluded.

        (d)     Notwithstanding anything to the contrary contained in this
Section 6.02 during the Term of this tease, Landlord agrees to appeal and/or
seek other appropriate remedies in the event that Landlord determines, in its
reasonable discretion, that the Real Estate Taxes for the Building or land upon
which it is situated are excessive when compared to assessments or levies
imposed or levied upon other buildings of a similar size, age, condition and
occupancy level located in Fair Lakes. Should Landlord succeed in any challenge
to the assessment or levy, any reduction of the Real Estate Taxes, for periods
occurring during the Term, shall be passed on to the tenants in the Building by
way of a credit against or a reduction in the current year's Real Estate Taxes
used to determine Tenant's Proportionate Share of the same. Upon receiving a
notice of reassessment with respect to the Building and/or the land upon which
it is situated from Fairfax County, Landlord will furnish Tenant with a copy
thereof. Landlord shall make a determination whether or not to challenge or
appeal such reassessment based on Landlord's reasonable judgment of which course
is in the best interest of the Building. Landlord shall inform Tenant of such
determination, and shall make available appropriate personnel to discuss with
Tenant the reasons underlying such determination. In the event Landlord
initially determines not to challenge or appeal such reassessment, Landlord
agrees to consider in good faith any desire expressed by Tenant that such
reassessment be challenged or appealed; however, the final determination shall
be made by Landlord as provided above.

        Section 6.03. Parking. During the Term, Tenant and its employees,
invitees, and guests shall have the right to use, in common, with the other
tenants of the Building, free of charge, the parking areas of the Building, all
on an unassigned and unreserved basis. Landlord reserves the right to promulgate
reasonable rules and regulations of general application for the use of all
parking spaces. At all times during the Term, Tenant shall be entitled to use
3.2 parking spaces in the Building's parking lot for each 1,000 square feet of
Rentable Area in the Premises. In the


                                      -16-
<PAGE>

event excessive use of the parking lot by other tenants or visitors to the
Building results in a repeated unavailability of spaces for Tenant's use in the
foregoing ratio, Landlord shall implement such controls on access to and use of
the parking lot by other tenants and visitors as Landlord may deem necessary in
its reasonable discretion to prevent such excessive use.

        Section 6.04. Additional Rent Defined. The term "Additional Rent" shall
include, but not be limited to (i) the fees, if any, under Section 5.07; (ii)
Tenant's Proportionate Share of Operating Expenses as calculated under Section
6.01; (iii) Tenant's Proportionate Share of Real Estate Taxes as calculated
under Section 6.02; and (iv) all other costs and expenses which Tenant assumes,
agrees or is required to pay to Landlord pursuant to this Lease. In the event of
nonpayment of Additional Rent, Landlord shall have all the rights and remedies
herein provided for in case of nonpayment of Rent.

        Section 6.05. Rent Defined. The term "Rent" shall include Base Rent and
Additional Rent.


                                  ARTICLE 7
                             SERVICES BY LANDLORD

        Section 7.01. Services Generally. While Tenant or its Permitted
Occupants (defined in Section 18.06 of this Lease) are occupying the Premises,
Landlord shall furnish the Premises with: (i) passenger elevator service in
common with other tenants for access to and from the Premises, provided that
Landlord may reasonably limit the number of elevators to be operated at night
after normal business hours and on Saturdays, Sundays, and holidays so long as
at least one elevator is in service at all times and that Landlord may remove
elevators from service for maintenance; (ii) janitorial cleaning services Monday
through Friday (except "Holidays", which for purposes of the Lease are defined
as being New Year's Day, Lee Jackson King Day, Washington's Birthday, Memorial
Day, Independence Day, Labor Day, Thanksgiving Day, Friday after Thanksgiving
Day and Christmas Day) consistent with the cleaning specifications attached
hereto as Exhibit "D"; (iii) replacement, as necessary, of all fluorescent lamps
and ballasts in the Existing Improvements light fixtures within the Premises;
and (iv) the utility services provided for in Article 8 below. If Tenant
requires services which are not specified herein Tenant may, in writing, request
Landlord to provide such services. Should Landlord elect to provide such
additional services to Tenant, Tenant will pay to Landlord, upon demand, as
Additional Rent, Landlord's reasonable charges for providing such additional
services.

        Section 7.02. Interruption in Services. Failure to furnish, or any
stoppage of, the services provided for in this Article 7 and in Article 8 below
resulting from any cause will not make Landlord liable in any respect for
damages to any person, property, or business, nor be construed as an eviction of
Tenant, nor entitle Tenant to any damages because of malfunctions or any
interruptions in service. Notwithstanding the foregoing, if such malfunction or
interruption in service is due solely to the negligent act or willful omission
of Landlord or its agents, employees, contractors or representatives, and such
malfunction or interruption in service (i) continues for two (2) consecutive
business days and (ii) makes it reasonably impossible for Tenant to continue to
occupy, operate and/or use the Premises (or portion thereof), and (iii) requires
Tenant to discon-


                                      -17-
<PAGE>

tinue its occupancy, operations and/or use of the Premises (or portion thereof),
then, and only in such cases, Tenant shall be entitled to an abatement of the
Rent accruing from the time of the disruption, for the portion of the Permission
which Tenant has discontinued its use, operations and/or occupancy. The
abatement shall be for the period commencing on the date of the malfunction or
interruption of services, and continuing until the date such service is
corrected or restored. Notwithstanding the foregoing, if the service has not
been corrected and restored and Tenant recommences its use, operations and/or
occupancy of a portion of the Premises in which its use, operations and/or
occupancy were discontinued because of the interruption in service, then,
Tenant's right to abate Rent applicable to the portion of the Premises
reoccupied shall terminate. In addition to the foregoing, if such malfunction or
interruption in service is caused by anything other than the negligence or
willful acts or omissions of Tenant, and such malfunction or interruption
continues for five (5) consecutive business days then Tenant shall be entitled
to an abatement of Rent with respect to any portion of the Premises that is
rendered unusable by Tenant as described above and which is not occupied by
Tenant, for the period commencing on the date of the malfunction or interruption
of services and continuing until earlier of the date such service is corrected
or restored and the date Tenant reoccupies the vacated space, provided that in
the event of an abatement of Rent Tenant shall be obligated to assign and
deliver to Landlord all proceeds it receives as a result of (i) any business
interruption insurance maintained by Tenant with respect to the Premises or (ii)
any other insurance maintained by Tenant for which Tenant receives a
reimbursement as a result of the malfunction or interruption of services. If any
such malfunction or interruption in service (not caused by the negligence or
willful acts or omissions of Tenant) continues for sixty (60) consecutive days,
then Tenant shall have the right to terminate this Lease by written notice to
Landlord given prior to the date such service is corrected or restored.


                                  ARTICLE 8
                                  UTILITIES

        Section 8.01. Computerized Energy Management System. The Building has
been designed with a Computerized Energy Management System (the "CEMS") which
controls the heating, ventilating and air conditioning system (the "HVAC") and
electrical system for the Premises, Tenant will designate to Landlord authorized
representatives of the Tenant who will be given, through the CEMS, direct
control of the HVAC and lighting system for use after normal Building hours.

        Section 8.02. Water, Heating, Ventilating and Air Conditioning.

        (a)     While Tenant or its subtenants or assigns permitted by this
Lease are occupying the Premises under this Lease, Landlord shall furnish Tenant
with the following utilities in the manner and to the extent customarily
provided in office buildings in the Northern Virginia area: (1) potable water at
those points of supply provided periodically for normal lavatory use by tenants
in the Building; (2) heating, ventilating, and air-conditioning in season on
business days from 7:00 a.m. to 6:00 p.m., and on Saturdays from 8:00 a.m. to
1:00 p.m. (except Holidays) consistent with the HVAC specifications attached
hereto as Exhibit "E"; and (3) electric lighting



                                      -18-
<PAGE>

for public areas and special service areas of the Building. If Tenant requires
air-conditioning or heating outside the hours and days specified above, the
additional service may be requested by use of the CEMS and Tenant will pay for
such services based on measurement from the CEMS at the actual cost incurred by
Landlord therefor. The after-hours cost, as of the Commencement Date of this
Lease, shall be $40.00 per hour per floor which is subject thereafter to change
as actual costs increase.

        (b)     Except as set forth in Article 7 hereof, Landlord shall not be
liable for its failure to maintain comfortable atmospheric conditions in all or
any portion of the Premises due to heat generated by any equipment or machinery
installed by Tenant (with or without Landlord's consent) that exceeds generally
accepted engineering design practices for normal modern office purposes. If
Tenant desires additional cooling to offset excessive heat generated by such
equipment or machinery, Landlord will have the right to require Tenant to
install supplemental air conditioning units in the Premises, and the full cost
thereof, including the cost of installation of unit(s) and meter(s), operation,
use, and maintenance will be paid by Tenant.

        Section 8.03. Electricity.

        (a)     While Tenant or its subtenants or assigns permitted by this
Lease are occupying the Premises, Landlord will furnish sufficient power for
lighting and for typewriters, word processors, calculating machines, copying
machines, personal computers and other modern office equipment. Tenant will not
install or operate in the Premises any heavy duty electrical equipment or
machinery without first obtaining prior written consent of Landlord, which
consent shall not be unreasonably withheld or delayed. Landlord may require, as
a condition of its consent, for the installation of such equipment or machinery,
payment by Tenant as additional rent for excess consumption of electricity that
may be occasioned by the operation of said equipment or machinery. Landlord may
make periodic inspections of the Premises at reasonable times to determine that
Tenant's electrically operated equipment and machinery complies with the
provisions of this Article 8.

        (b)     If the measurements from the CEMS reveals Tenant's use of
electricity in the Premises exceeds a reasonable level of consumption for a
modern business office, then Tenant agrees to pay Landlord (or the utility
company if direct service is provided by such company) promptly upon demand
therefor, for all such excessive electric consumption and demand as shown by the
CEMS at the rates charged for such service by the local public utility company.
For Tenant's information, provisions similar to this subparagraph are and will
be contained in all leases for the Building.

        Section 8.04. Tenant's Security Regulations. It is acknowledged that
Tenant's use of the Premises may require security systems in addition to those
provided pursuant to Section 8.05. Tenant shall have the right, at its sole cost
and expense, to install in the Premises additional locks or other security
access systems. Upon the Expiration Date, Tenant shall remove such additional
locks and security systems and restore the affected portions of the Premises as
required by this Lease.




                                      -19-
<PAGE>

        Landlord agrees that, notwithstanding anything to the contrary contained
in this Lease, except in emergency situations, Landlord's access to the Premises
will be upon reasonable prior notice to Tenant and subject to Tenant's rules and
regulations related to security. Landlord and Tenant agree to cooperate with
each other so as to establish a mutually acceptable system so as to permit
Landlord to provide janitorial and other services to the Premises in a manner
consistent with Tenant's security concerns.

        Section 8.05. Building Security System. The Building has been
constructed with a card access computerized security system which limits access
to the Building after normal Building hours. Tenant will designate in writing to
Landlord those employees of the Tenant who will be given access to the Building
after hours. Landlord will have no liability to Tenant in the event of any loss
or damage to the Premises resulting from the entry by Tenant's employees into
the Premises and/or Building after normal Building hours.


                                  ARTICLE 9
                                     USE


        The Premises shall be used solely for general office purposes and for no
other purpose. Tenant agrees to use and maintain the Premises in a clean,
careful, safe, lawful, and proper manner.


                                  ARTICLE 10
                             COMPLIANCE WITH LAWS


        (a)     Except as set forth in subparagraph (b) of this Article or
otherwise to the contrary contained in this Lease, Tenant shall, at its sole
expense, promptly and faithfully (i) comply with all present and future laws,
ordinance, orders, rules, regulations, and requirements of every governmental
authority having jurisdiction over the Premises (including, but not limiting
the generality of the foregoing Americans with Disabilities Act 42 USC Section
12101 et seq. (the "ADA")) to the extent applicable to the Premises or Tenant's
particular use of the Premises; (ii) comply with any direction made pursuant to
law by any public officers which requires abatement of any nuisance or imposes
upon Landlord or Tenant any duty or obligation arising from Tenant's occupancy
or use of the Premises or from conditions which have been created by or at the
insistence of Tenant, (iii) comply with the requirements of the local board of
fire underwriters, or any body exercising similar functions with respect to the
construction, care and safety, maintenance and operation of the Premises to the
extent applicable to the Premises or Tenant's use of the Premises; and (iv)
indemnify Landlord and hold Landlord harmless from any loss, cost, claim, or
expense which Landlord may incur or suffer by reason of Tenant's failure to
comply with its obligations under clauses (ii), or (iii) above, so long as such
failure is not due to (i) the acts or omission or negligence of Landlord or its
employees, agents, contractors, servants and licensees or (ii) a default by
Landlord hereunder.

        (b)     Except as set forth in subparagraph (a) of this Article or
otherwise assumed by Tenant pursuant to this Lease, Landlord shall promptly and
faithfully (i) comply with all present and future laws, ordinances, orders,
rules, regulations and requirements of every governmental


                                      -20-
<PAGE>

authority having jurisdiction over the Building (including, but not limiting the
generality of the foregoing, the items maintained by Landlord pursuant to
Section 14.02 hereof); (ii) comply with any direction made pursuant to law by
and public officers which require abatement of any nuisance which imposes upon
Landlord or Tenant any duty or obligation arising from Landlord's operation or
maintenance of the Building or from conditions which have been created by or at
the insistence of Landlord; (iii) comply with the requirements of the local
board of fire underwriters, or any body exercising similar functions with
respect to the construction, care and safety, maintenance and operation for the
Building; and (iv) indemnify Tenant and hold Tenant harmless from any loss,
cost, claim, or expense which Tenant may incur or suffer by reason of Landlord's
failure to comply with its obligations under clauses (i), (ii), or (iii) above,
so long as such failure is not due to (i) the acts or omissions or negligence of
Tenant or its employees, agents, contractors, servants and licensees; or (ii) a
Default by Tenant hereunder.

        (c)     Landlord represents that as of the date hereof and as of the
Commencement Date, the Building complies with all applicable laws, ordinances,
orders, rules and regulations and requirements of every governmental authority
having jurisdiction over the Building, except as it pertains to the ADA.
Landlord, as of the date of this Lease, is currently implementing a program to
remove barriers in the common areas of the Building as required by the ADA and
shall complete the same at its sole cost and expense. A copy of Landlord's
barrier removal program is attached as Exhibit "F".

        (d)     If either party receives notice of any such direction or of
violation of any such law, order, ordinance, or regulation, the party receiving
such notice shall promptly notify the other thereof.


                                  ARTICLE 11
                        OBSERVANCE OF BUILDING'S RULES
                     AND REGULATIONS; HAZARDOUS MATERIALS

        Section 11.01. Rules and Regulations. Tenant and its servants,
employees, agents, visitors, and licensees shall observe faithfully and comply
strictly with the Rules and Regulations attached to this Lease as Exhibit "G".
Landlord shall at all times have the right to make reasonable changes in and
additions to such Rules and Regulations; provided such changes in existing or
new rules and regulations do not materially interfere with the lawful conduct of
Tenant's business in the Premises. Any failure by Landlord to enforce any of the
Rules and Regulations now or hereafter in effect, either against Tenant or any
other tenant in the Building, shall not constitute a waiver of any such Rules
and Regulations. Landlord shall not be liable to Tenant for the failure or
refusal by any other tenant, guest, invitee, visitor, or occupant of the
Building to comply with any of the Rules and Regulations. Landlord shall,
however, enforce the Rules and Regulations in a nondiscriminatory manner in what
Landlord reasonably determines, in its reasonable discretion, to be in the best
interests of the Building and its tenants. If there is any inconsistency between
this Lease and the Rules and Regulations set forth in Exhibit "G" hereto, this
Lease shall govern.



                                      -21-
<PAGE>

        Section 11.02. Hazardous Materials.

        (a)     Except for those materials that are necessary in the normal
course of Tenant's business activities associated with the use of the Premises
permitted by this Lease, Tenant, its agents, employees, contractors or invites
shall not (i) cause or permit any Hazardous Materials (hereinafter defined) to
be brought upon, stored, used or disposed on, in or about the Premises and/or
the Building, or (ii) permit the release, discharge, spill or emission of any
substance considered to be a Hazardous Material from the Premises.

        (b)     Any Hazardous Materials permitted by subparagraph (a), all
containers therefor, and all materials that have been contaminated by Hazardous
Materials shall be used, kept, stored and disposed of by Tenant in a manner that
shall in all respects comply with all applicable federal, state and local laws,
ordinances, regulations and standards.

        (c)     Tenant hereby agrees that it is and shall be fully responsible
for all costs, expenses, damages or liabilities (including, but not limited to
those incurred by Landlord and/or its mortgagee) which may occur from the use,
storage, disposal, release, spill, discharge or emissions of Hazardous Materials
by Tenant whether or not the same may be permitted by this Lease. Tenant shall
defend, indemnify and hold harmless Landlord, its mortgagee and its agents from
and against any claims, demands, administrative orders, judicial orders,
penalties, fines, liabilities, settlements, damages, costs or expenses
(including, without limitation, reasonable attorney and consultant fees, court
costs and litigation expenses) of whatever kind or nature, known or unknown,
contingent or otherwise, arising out of or in any way related to the use,
storage, disposal, release, discharge, spill or emission of any Hazardous
Material by Tenant, its agents, employees, contractors or invites. The
provisions of this Section shall be in addition to any other obligations and
liabilities Tenant may have to Landlord at law or in equity and shall survive
the transactions contemplated herein or any termination of this Lease.

        (d)     As used in this Lease, the term "Hazardous Materials" shall
include, without limitation:

        (i)     Those substances included within the definitions of "hazardous
                substances", "hazardous materials," toxic substances," or "solid
                waste" in the Comprehensive Environmental Response Compensation
                and Liability Act of 1980 (42 U.S.C. Section 9601 et seq.), as
                amended by Superfund Amendments and Reauthorization Act of 1986,
                the Resource Conservation and Recovery Act of 1976, and the
                Hazardous Materials Transportation Act, and in the regulations
                promulgated pursuant to said laws, all as amended;

        (ii)    Those substances listed in the United States Department of
                Transportation Table (49 CFR 172.101 and amendments thereto) or
                by the Environmental Protection Agency (of any successor agency)
                as hazardous substances (40 CFR Part 302 and amendments
                thereto);

        (iii)   Any material, waste or substance which is (A) petroleum, (B)
                asbestos, (C) polychorinated biphenyls, (D) designated as a
                "hazardous substance" pursuant to Sec-





                                      -22-
<PAGE>

                tion 311 of the Clean Water Act, 33 U.S.C. Section 1251 et seq.
                (33 U.S.C. Section 1321) or listed pursuant to Section of the
                Clean Water Act (33 U.S.CD. Section 1317); (E) flammable
                explosives; or (F) radioactive materials;

        (iv)    Those substances regulated pursuant to or identified in the
                Virginia Pesticide Law; Air Pollution Control Board; Virginia
                Waste Management Act; Environmental Health Service;
                Transportation of Hazardous Radioactive Materials; Virginia
                Hazardous Materials Emergency Response Program; State Water
                Control Law; The Groundwater Act of 1973; and Miscellaneous
                Offenses; and in the regulations promulgated pursuant to said
                laws, all as amended; and

        (v)     Such other substances, materials and wastes which are or become
                regulated as hazardous or toxic under applicable local, state or
                federal law, or the United States government, or which are
                classified as hazardous or toxic under federal, state, or local
                laws or regulations.

        (e)     Landlord represents and warrants that as of the date of this
Lease it has not received any notice that there are Hazardous Materials in the
Building; or that the Building violates any applicable law pertaining to
Hazardous Materials.


                                  ARTICLE 12
                                 ALTERATIONS

        Section 12.01. Approval of Landlord. After the initial Leasehold
Improvements are completed, Tenant shall not, at any time during the Term,
without Landlord's prior written consent, make any Alterations (hereinafter
defined) to the Premises. Should Tenant desire any Alterations, Tenant agrees to
submit all plans and specifications for same to Landlord for Landlord's written
approval, before beginning such work and Landlord's approval shall not be
unreasonably withheld, conditioned or delayed. Provided Tenant has supplied
Landlord with information and plans for the Alterations which reasonably details
the nature and scope of the same, Landlord's failure to respond to Tenant's
request for approval within ten (10) business days after receipt of the
information, plans and request for approval, shall be deemed to be Landlord's
approval of the same. Landlord shall not be considered as unreasonably
withholding its approval by refusing to consent to any Alterations which alter
the exterior appearance of the Building, or the public lobbies, corridors, or
common areas thereof; which will or are likely to cause any weakening of any
part of the structure of the Premises or Building or which may cause damage or
disruption to any Building system and such damage or disruption is not repaired
as part of the Alterations. Upon Tenant's receipt of Landlord's written
approval, Tenant may proceed with the construction of the approved Alterations,
but only so long as they are in substantial compliance with the plans any
specifications approved by Landlord and provisions of this Article 12.
Additionally, the construction of any alterations, (regardless of whether or not
Landlord's prior approval of the work is required by this Lease) the alterations
themselves, or any maintenance thereof shall comply with all building, safety,
fire, plumbing, electrical and other codes and governmental and insurance
requirements, and shall not require an amount of water, electricity, gas, heat,
ventilation, or air-conditioning which exceeds reasonable level of consumption
for a mod-


                                      -23-
<PAGE>

ern business office unless prior written arrangements reasonably satisfactory to
Landlord are made with respect thereto. All alterations shall be made at
Tenant's expense, either by Tenant's contractors which have been approved in
advance by Landlord or, at Tenant's option, by Landlord's contractors on terms
reasonably satisfactory to Tenant. In the event Landlord actually constructs the
alterations or is retained by Tenant to supervise or manage the construction by
contractors selected by Tenant and approved by Landlord, then Tenant shall pay
to Landlord a fee equal to ten percent (10k) of the actual costs of such work,
such fee to cover Landlord's overhead related to the work, including, but not
limited to, Landlord's review of the plans and specifications, coordination of
the work, consultation with professionals regarding the work, and general
administration allocable to the work. The foregoing fee will not be charged in
circumstances where Landlord has merely approved the Alterations. All such
construction shall be completed promptly and in a good and workmanlike manner
and shall be performed in compliance with Article 13 hereof.


        As used in this Lease, the term Alterations refers to work performed
after the completion of the initial Leasehold Improvements which would
reasonably be considered major construction, renovations or changes to the
Premises, having a material impact on the appearance of the Premises to other
portions of the Building, or would otherwise have a material impact (structural,
mechanical, operational or otherwise) upon the Building, and/or the total cost
of the construction renovations or changes is more than $75,000.00. Alterations
do not include, by way of example, the hanging of pictures, the movement of
furniture and flexible space walls or partitions, or the painting of the
interior of the Premises. Prior to commencing any alterations, Tenant will
coordinate with Landlord so as to schedule the movement of men, material and
equipment through the Building's common areas in a manner which does not
unreasonably interrupt the normal Building operations and the use and enjoyment
of the Building by other tenants therein.

        Section 12.02. Ownership of Improvements to Premises. All Existing
Improvements and improvements to the Premises constructed by Tenant and paid for
by Tenant from funds supplied by Landlord either in the form of allowances or
credits shall be and remain the Landlord's property, and shall not be removed
from the Premises. Tenant shall have the right, upon expiration of the Term, to
remove, at Tenant's expense, all alterations to the Premises (other than the
Existing Improvements and the improvements or alterations paid by allowances
granted by Landlord); specialized trade fixtures or other systems or items
installed by Tenant pursuant to Article 12 hereof, and; movable trade fixtures.
Tenant agrees to remove, at Tenant's expense all of its furnishings, furniture
and movable personal property by the Expiration Date. Tenant will promptly
restore any damage to the Premises or Building caused by its removal of its
property.


                                  ARTICLE 13
                                    LIENS


        Tenant shall promptly pay when due the entire cost of any work done on
the Premises by Tenant, its agents, employees, or independent contractors.
Tenant shall keep the Premises and the Building free from any liens arising from
any work performed, materials furnished, or obligations incurred by or at the
request of Tenant, its agents, employees or independent contractors. if any lien
is filed against the Premises, the Building or Tenant's leasehold interest
therein, which


                                      -24-
<PAGE>

arises out of any purported act or agreement of Tenant, Tenant shall discharge
same within thirty (30) days after its filing by either paying off the same or
depositing with a title company acceptable to Landlord (in its reasonable
discretion) such bond or other undertaking sufficient to stay any action to
foreclose the lien. If Tenant fails to discharge such lien or post a bond
securing the payment and discharge of the lien within such period, then, in
addition to any other right or remedy of Landlord, Landlord may, at its
election, discharge the lien by paying the amount claimed to be due, or by
depositing with a court or a title company, or by bonding, the amount claimed to
be due. Tenant shall pay on demand, as Additional Rent, any amount paid by
Landlord for the discharge or satisfaction of any such lien, and all attorney's
fees and other costs and expenses of Landlord reasonably incurred in defending
any such action or in obtaining the discharge of such lien, together with all
necessary disbursements in connection therewith. In the event Tenant posts a
bond to secure payment of a lien, such action does not relieve Tenant of its
obligation to discharge the lien prior to its foreclosure. Further, Landlord
reserves the right to draw upon any bond posted by Tenant to pay any lien if
Landlord, in its reasonable discretion, determines it is necessary to discharge
the same.


                                  ARTICLE 14
                                   REPAIRS

        Section 14.01. Tenant's Obligations. Tenant shall keep the Premises and
every part thereof in good condition and repair at all times during the Term and
at Tenant's sole cost and expense, normal wear and tear excepted. At the end of
the Term, Tenant shall surrender to Landlord the Premises and all alterations,
additions, and improvements thereto in the same condition as when received,
subject to the provisions of Section 12.02 and Article 20 hereof. Landlord shall
give Tenant five (8) business days notice to commence to make repairs. If Tenant
fails to commence to make such repairs within such time period, Landlord, at its
option, may make such repairs, and Tenant shall pay Landlord on demand
Landlord's actual costs in making such repairs plus a fee of ten percent (10W)
to cover Landlord's overhead, all to constitute Additional Rent. Landlord has no
obligation and has made no promise to alter, remodel, improve, repair, decorate,
or paint the Premises or any part thereof, except as specifically set forth in
this Lease. No representations respecting the condition of the Premises or the
Building have been made by Landlord to Tenant except as specifically herein set
forth.

        Section 14.02. Landlord's Obligations. Subject to the other provisions
of this Lease imposing obligations in this respect upon Tenant, and subject to
the provisions of Articles 16 and 17 hereof, Landlord shall, at its sole cost
and expense (but, subject, where applicable, to inclusion as part of the
Operating Expenses), repair, replace, and maintain:

        (i)     All common areas of the Building, including without limitation,
                the sidewalks, driveways, service areas and parking areas;

        (ii)    The exterior and structure of the Building and the Premises,
                including without limitation, the roof (including flashings and
                water tightness of the Building), walls (including caulking),
                floors and foundations and the landscaping for the Building;





                                      -25-
<PAGE>

        (iii)   The Building systems, including without limitation, heating,
                ventilating, air conditioning and sprinkler systems; and

        (iv)    The Building water, sewerage, gas, electrical, life safety
                systems, plumbing systems and other lines, pipes and conduits
                within the Building and the Premises.


                                  ARTICLE 15
                                  INSURANCE

        Section 15.01. Tenant's Insurance. Tenant, at its sole expense, shall
obtain and keep in force the, following insurance:

        (a)     Comprehensive public liability insurance coverage on an
"occurrence basis" against claims for personal injury, including, without
limitation, bodily injury, death, and broad form property damage, in limits not
less than $5,000,000 inclusive. All such insurance policies shall name Tenant as
the named insured thereunder and shall name Landlord and Landlord's mortgagees
as additional insureds thereunder, all as their respective interests may appear.

        (b)     Worker's Compensation and Employer's Liability insurance, with a
waiver of subrogation endorsement, in form and amount satisfactory to Landlord.

        (c)     All Risk Insurance insuring all personal property of Tenant (its
agents, employees, contractors, subtenants and permittees) located in the
Premises, including furniture, equipment fittings, installations, supplies and
any other personal property and Alterations ("Tenant's Property"), in an amount
equal to the full replacement value, it being understood that no lack or
inadequacy of insurance by Tenant shall in any event make Landlord subject to
any claim by virtue of any theft or loss or damage to any uninsured or
inadequately insured property; and

        (d)     During the course of construction of work, should any work be
performed by Tenant pursuant to Exhibit "B" or for any alterations by Tenant
until completion thereof: Builder's Risk Insurance on an "all risk" basis
(including collapse) on a completed value (nonreporting) form for full
replacement value covering all work incorporated in the Building and all
materials and equipment in or about the Premises.

        All policies shall be issued by companies having a Best's rating of at
least A:XII and shall be in amounts and in form satisfactory from time to time
to Landlord and Landlord's mortgagees. All policies shall contain an endorsement
or agreement by the insurer that, as to Landlord's interest, any loss shall be
payable in accordance with the terms of such policy notwithstanding any act or
negligence of Tenant which might otherwise result in forfeiture of said
insurance. Tenant will deliver certificates of insurance evidencing each policy
to Landlord as soon as practicable after the placing of the required insurance,
but not later than ten (10) days prior to the date Tenant takes possession of
all or any part of the Premises. All policies shall contain an undertaking by
the insurers to notify Landlord and Landlord's mortgagees in writing, by
Registered or Certified U.S. Mail, return receipt requested, not less than
thirty (30) days before any material change., reduction in the scope or limits
of coverage, cancellation, or other termination thereof.




                                      -26-
<PAGE>


        Landlord reserves the right, not more often than once every year, to
periodically review the insurance coverages required by this Section 15.01 and
to revise such requirements to reflect insurance industry practices or require
other forms or amounts of insurance as may be reasonably required to reflect
changes in insurance industry practices.

        Section 15.02. Insurance Rating. Tenant will not keep, use, sell, or
offer for sale in, or upon, the Premises any article which may be prohibited by
any insurance policy periodically in force covering the building and the
Leasehold Improvements. If Tenant's occupancy or business in, or on, the
Premises, whether or not Landlord has consented to the same, results in any
increase in premiums for the insurance periodically carried by Landlord with
respect to the Building or the Leasehold Improvements, Tenant shall pay any such
increase in premiums as Additional Rent within ten (10) days after being billed
therefor by Landlord.


        If any of Landlord's insurance policies shall be canceled or
cancellation shall be threatened or the coverage thereunder reduced or
threatened to be reduced in any way because of the use of the Premises or any
part thereof by Tenant or any assignee or sub-tenant of Tenant or by anyone
Tenant permits on the Premises and, if Tenant fails to remedy the condition
giving rise to such cancellation, threatened cancellation, reduction of
coverage, or threatened reduction of coverage within 48 hours after notice
thereof, Landlord may enter upon the Premises and attempt to remedy such
condition, and Tenant shall promptly pay the cost thereof to Landlord as
Additional Rent. Landlord shall not be liable for any damage or injury caused to
any property of Tenant or of others located on the Premises resulting from such
entry. If Landlord is unable or elects not to remedy such condition, then
Landlord shall have all of the remedies provided for in this Lease in the event
of a Default by Tenant. Notwithstanding the foregoing provisions of this
Section, if Tenant fails to remedy as aforesaid, Tenant shall be in Default of
its obligations hereunder and Landlord shall have no obligation to remedy such
Default.

        Section 15.03. Waiver of Subrogation. All policies covering real or
personal property which either party obtains affecting the Premises shall
include a clause or endorsement denying the insurer any rights of subrogation
against the other party to the extent rights have been waived by the insured
before the occurrence of injury or loss, if same are obtainable. Landlord and
Tenant waive any rights of recovery against the other for injury or loss due to
hazards covered by policies of insurance containing such a waiver or subrogation
clause or endorsement to the extent of the injury or loss covered thereby.

        Section 15.04. Landlord Insurance. Landlord, as part of the Operating
Expenses, shall obtain and keep in force the following insurance:

        (a)     Comprehensive public liability insurance coverage on an
"occurrence basis" against claims in or about the Building (other than the
Premises) for personal injury, including without limitation, bodily injury,
death and broad form property damage, in limits not less than $5,000,000
inclusive;

        (b)     Workmen's Compensation and Employer's Liability Insurance;





                                      -27-
<PAGE>

        (c)     All Risk Insurance insuring the Landlord's interest in the
Building, all Leasehold Improvements in the Premises constructed by Tenant using
funds supplied by Landlord (specifically excluding, Tenant's personal property
and all improvements in the Premises erected by Tenant using its own funds which
under Virginia law are considered fixtures (the "Fixtures")) in a form
satisfactory to Landlord and in an amount equal to the full replacement value of
the Landlord's insurable interest in the Building; and

        (d)     Any other form or forms of insurance as Landlord, or Landlord's
mortgagees may reasonably require from time to time in form, in amounts, and for
insurance risks against which a prudent Landlord of a comparable size and in a
comparable business would protect itself.

        Section 15.05. Self Insurance and Blanket Insurance. Landlord and Tenant
shall have the right to satisfy its obligations under this Article through the
use of self-insurance and blanket insurance programs so long as the coverages,
and limits otherwise satisfy this Article. Tenant's rights under this Section
15.04 are personal to the Tenant named herein and its Parent or Affiliates (as
hereinafter defined).


                                  ARTICLE 16
                       DAMAGE BY FIRE OR OTHER CASUALTY

        Section 16.01. Termination Rights Due to Damage or Destruction to the
Premises.

        (a)     Landlord and Tenant shall each immediately notify the other of
any damage to the Building which affects the Premises.

        (b)     If all or any portion of the Premises are damaged and destroyed
(such area being hereinafter referred to as the "Damaged Area"), Landlord shall
cause Landlord's architect for the Building (the "Building Architect"), to
inspect the Premises. Within thirty (30) days after the damage and destruction,
the Building Architect shall complete its inspection and notify Landlord and
Tenant, in writing, of its findings (the "Damage Report").

        (c)     Should the Building Architect, in the exercise of its reasonable
objective opinion, determine in the Damage Report that the Damaged Area can be
rebuilt but either (i) the reconstruction can not be completed and the Damaged
Area made fit for Tenant's purposes within one hundred (100) days after the
damage or destruction, or (ii) when rebuilt, the Damaged Area cannot be
reasonably occupied or used for the continued operation of the Tenant's
business, then, in either case, Tenant shall have the right, at its sole option,
to terminate this Lease as it pertains to the Damaged Area. In such case, Tenant
may exercise its right to terminate this Lease by giving written notice to
Landlord, within sixty (60) days after receipt of the Damage Report.

        (d)     Should the Damage Report reveal that the provisions of
subparagraph (c) of this Section do not apply and the Damaged Area can be
rebuilt and made fit for Tenant's continued use, but the proceeds of the
insurance which Tenant is required to maintain under Section 15.01(c) that was
intended to cover the Tenant's Property, are insufficient to repair or restore
the damage or destruction, then Landlord and Tenant will each have a right to
terminate this Lease as it pertains to the Damaged Area. In such case, Landlord
or Tenant may exercise their respective


                                      -28-
<PAGE>

right to terminate as to the Damaged Area, by giving notice to the other, within
sixty (60) days after receipt of the Damage Report.

        Section 16.02. Damage to the Building.

        (a)     If the Building or any portion thereof (excluding the Premises)
is damaged or destroyed by any cause whatsoever, to the extent that in
Landlord's reasonable judgment, it would not be economically feasible to repair
or restore such damage or destruction, Landlord may, at its option, terminate
this Lease by giving Tenant notice of such termination within sixty (60) days
after such damage or destruction.

        (b)     Provided the provisions of subparagraph (a) are not applicable
the Building Architect will notify Landlord and Tenant, if, in the Building
Architect's reasonable objective judgment, the damage or destruction to the
Building I cannot be repaired or restored within three hundred sixty (360) days
after such damage or destruction. Landlord or Tenant shall have the right, at
the option of either party, to terminate this Lease. In such case, Landlord or
Tenant may exercise their respective right to terminate this Lease by giving
written notice to the other, within sixty (60) days after receipt of the
Building Architect's notification and thereupon the provisions of Section 16.06
hereof shall apply.

        (c)     If any portion of the Building (excluding the Premises) is
damaged or destroyed by any cause whatsoever to the extent that the Building
Architect determines that such damage makes it reasonably impossible for Tenant
to continue to use or occupy the Premises, then either Landlord or Tenant shall
have the right, at the option of either party, to terminate this Lease as to the
portion of the Premises affected by such damage or destruction by giving the
other, within sixty (60) days after such damage or destruction, written notice
of termination, and thereupon Rent and any other payments for which Tenant is
liable under this Lease for the portion of the Premises affected shall be
apportioned and paid to the date of such damage, and Tenant shall immediately
vacate the affected portion of the Premises; provided, however, that those
provisions of this Lease which are designated to cover matters of termination
and the period thereafter shall survive the termination hereof.

        Section 16.03. Partial Damage. In the event of partial destruction or
damage to the Building or the Premises which does not result in a complete
termination of this Lease pursuant to Sections 16.01 and 16.02 hereof, this
Lease shall not terminate and Rent shall be abated in proportion to the area of
the Premises which, in the Building's Architect's reasonable objective opinion,
cannot be used or occupied by Tenant as a result of such casualty. Landlord
shall in such event, within a reasonable time after the date of such destruction
or damage, restore the Premises to as near the same condition as existed prior
to such partial damage or destruction, provided that Tenant shall be responsible
for restoring its personal property. Upon such reconstruction, the Rentable Area
of the Premises will be recomputed and Tenant's Proportionate Share adjusted
accordingly.

        Section 16.04. Damage During Last Year of Term. If the Building or the
Premises or any substantial portion thereof is destroyed by fire or other causes
at any time during the last year of the Term, then either Landlord or Tenant
shall have the right, at the option of either party, to


                                      -29-
<PAGE>

terminate this Lease by giving written notice to the other within sixty (60)
days after the date of such destruction, and Tenant shall immediately vacate the
Premises and, upon Tenant's vacation of the Premises, this Lease shall
terminate.

        Section 16.05. No Landlord Liability. Landlord shall have no
responsibility to restore the Tenant's personal property, except as specifically
provided in Sections 16.01(d) and 16.03. Landlord shall have no liability to
Tenant for inconvenience, loss of business, or annoyance arising from any repair
of any portion of the Premises or the Building. If Landlord is required by this
Lease or by any lender or lessor of Landlord to repair or if Landlord undertakes
to repair, Tenant shall pay to Landlord that amount of Tenant's insurance
proceeds which insures such damage as a contribution towards such repair, and
Landlord shall use reasonable efforts to have such repairs made promptly and in
a manner which will not unnecessarily interfere with Tenant's use and occupancy.
Notwithstanding the foregoing, if such repairs continue for two (2) consecutive
days and make it reasonably impossible for Tenant to continue to occupy, operate
and/or use the Premises, Tenant shall be entitled an abatement of Rent payable
at the time of such disruption for the portion of the Premises affected by the
repairs for the period commencing on the date of the interruption caused by the
repairs, and continuing until the earlier of (i) the date such repair is
completed, or (ii) the date such disruption ceases. However, should Tenant
recommence its use, occupancy and/or operations in any part of the Premises
which was affected by the repairs, notwithstanding the fact that the repairs may
not have been completed, Tenant's right to abate Rent for the reoccupied portion
of the Premises will terminate.

        Section 16.06. Apportionment of Rent. In the event of termination of
this Lease pursuant to Section 16.01, then all Rent shall be apportioned and
paid to the date on which possession is relinquished or the date of such damage,
whichever last occurs, and Tenant shall immediately vacate the Premises
according to such notice of termination and upon such vacation, the Lease will
terminate as to the portion of the Premises affected thereby.


                                  ARTICLE 17
                                 CONDEMNATION

        Section 17.01. Entire Building. In the event that the whole or
substantially the whole of the Building and/or the Premises are taken or
condemned for any public purpose, this Lease and the leasehold estate created
hereby shall cease and terminate as of the date of such taking.

        Section 17.02. Partial Takings Affecting the Premises.

        (a)     In the event that either (i) a portion, but less than
substantially the whole, of the Premises should be taken or condemned for any
public purpose, and the remainder of the Premises cannot be reasonably used for
the continued operation of Tenant's business or (ii) a portion, but not all, of
the Building is taken and such taking makes it reasonably impossible for Tenant
to continue to occupy, operate and/or use the Premises, then in either event,
either party may terminate this Lease by written notice to the other given
within thirty (30) days of such taking and then this Lease shall be terminated
as of the date of such taking.




                                      -30-
<PAGE>

        (b)     For all circumstances not addressed in Sections 17.01 and
17.02(a), in the event of a partial taking of the Premises, this Lease shall be
terminated as of the date of such taking as to the portion of the Premises so
taken or affected by such taking, and, this Lease shall remain in full force and
effect as to the remainder of the Premises. In such event, the Rent will be
diminished by an amount representing the part of such amounts properly
applicable to the portion of the Premises so taken. Further, in such event
Tenant's Proportionate Share shall be recomputed based upon the remaining
Rentable Area in the Premises and in the Building.

        Section 17.03. Termination of Lease. In the event of the termination of
this Lease pursuant to the provisions of this Article 17, this Lease and the
Term and the estate hereby granted shall expire as of the date of such
termination in the same manner and with the same effect as if that were the date
set for the normal expiration of the Term of this Lease, and the Rent shall be
apportioned as of such date.

        Section 17.04. Landlord's Right to Award. All awards, damages, and other
compensation paid by the condemning authority on account of such taking or
condemnation (or sale under threat of such a taking) shall belong to Landlord,
and Tenant hereby assigns to Landlord all rights to such awards, damages and
compensation. Tenant agrees not to make any claim against Landlord or the
condemning authority for any portion of such award or compensation attributable
to damages to the Premises, the value of the unexpired term of this Lease, the
loss of profits or goodwill, Leasehold Improvements paid by Tenant by the use of
the Tenant Allowance or severance damages. Nothing contained herein, however,
shall prevent Tenant from pursuing a separate claim against the condemning
authority for the value of Leasehold Improvements paid by Tenant from funds
other than the Tenant Allowance, Alterations paid by Tenant, furnishings,
equipment, and trade fixtures installed in the Premises at Tenant's expense and
for relocation expenses.


                                  ARTICLE 18
                          ASSIGNMENT AND SUBLETTING

        Section 18.01. Permitting Subletting of the Premises.

        (a)     Tenant shall have the right to sublet the Premises without the
prior consent of Landlord so long as

        (i)     the sublease has provisions which satisfy Section 18.03 hereof;

        (ii)    the entity, organization or individual to which the space is
                sublet satisfies the requirements of Section 18.02(b)(ii) and
                (iii) hereof; and

        (iii)   the total Rentable Area of the Premises occupied by Tenant or
                its Permitted Occupants is not less than 50% of the Rentable
                Area demised by this Lease.

        (b)     In the event of a sublease, Tenant shall submit to Landlord
evidence that the provisions of Section 18.01(a) have been satisfied. Should the
sublease result in a violation of the


                                      -31-
<PAGE>

provisions of Section 18.01(a) then such sublease shall be subject to the
provisions of Section 18.02 hereof.

        (c)     Notwithstanding the foregoing or the provisions of Section 18.02
hereof, the Premises or any part thereof shall not be publicly advertised in
newspapers or other mass media for subletting at a rental rate less than the
rental rate being sought by Landlord for space in the Building (provided that
Landlord shall, within ten (10) days after Tenant so requests, have informed
Tenant of the rental rate being sought by Landlord for such space), and all
advertisements (in newspapers or other mass media) of the Premises or any
portion thereof for subletting shall not include the name of the Building
(without Landlord's prior written consent which will not be unreasonably
withheld). The foregoing, however, shall not be deemed to prohibit Tenant from
negotiating or consummating a sublease at a lower rental rate.

        Section 18.02. Rights of Tenant.

        (a)     Except as permitted by Sections 18.01(a) and 18.06 hereof,
Tenant may not sell, assign, transfer, or hypothecate this Lease or any interest
herein (either voluntarily or by operation of law, and including, if Tenant is a
corporation or partnership, the sale or transfer of a controlling interest in
Tenant), or sublet the Premises or any part hereof without the prior written
consent of Landlord, which shall not be unreasonably withheld, conditioned or
delayed. If Tenant should desire to assign this Lease or sublet the Premises (or
any part thereof), Tenant shall give Landlord written notice at least fifteen
(15) days in advance of the date on which Tenant desires to make such assignment
or sublease. Landlord shall then have a period of ten (10) days following
receipt of such notice within which to notify Tenant in writing that landlord
elects:

        (i)     to permit Tenant to assign or sublet such space, subject,
                however, to the subsequent written approval by Landlord of the
                instrument of assignment or sublease as to form and substance;
                or

        (ii)    to refuse, in Landlord's reasonable discretion, to consent to
                Tenant's assignment or subleasing of such space and to continue
                this Lease in full force and effect as to the entire Premises.
                If Landlord should fail to notify Tenant in writing of such
                election within such ten (10) day period, Landlord shall be
                deemed to have elected option (i) above.


        Except as may be otherwise expressly set forth to the contrary in
Landlord's consent to the assignment, no assignment by Tenant shall relieve
Tenant of Tenant's obligations under this Lease. Any attempted assignment or
sublease by Tenant which is not permitted by Section 18.01 and 18.06 hereof and
is in violation of the terms and provisions of this Section shall be void.

        (b)     Landlord's consent under this Section 18.02(a) to an assignment
or sublease will not be withheld provided all of the following conditions have
been satisfied:

        (i)     if a sublease, the sublease has provisions which satisfy Section
18.03 hereof;




                                      -32-
<PAGE>

        (ii)    if an assignment, (a) the assignee shall agree, in a written
                agreement satisfactory to Landlord, to assume and abide by all
                of the terms and provisions of this Lease (but without liability
                to matters arising prior to the date of the assignment); and (b)
                the assignee has submitted a current financial statement
                reasonably acceptable to Landlord, showing a net worth and
                working capital in amounts reasonably determined by Landlord to
                be sufficient to assure the future performance by such assignee
                of Tenant's obligations hereunder; and

        (iii)   the entity, organization, or individual to which such space is
                proposed to be sublet or to which the Lease is proposed to be
                assigned is not of a type that would be an undesirable tenant in
                a first-class office complex in Fair Lakes, or of a type that
                because of its controversial or unsavory nature, might bring
                undue notoriety or disruption to the Building.

        Section 18.03. Required Provision in Sublease. A sublease of portions of
the Premises, must include (or shall be deemed to include) provisions stating
that it is subject and subordinate to this Lease and to the matters to which
this Lease is or shall be subordinate, and that in the event of the termination
of this Lease, or the re-entry or dispossession of Tenant by Landlord under this
Lease, the sublease shall also terminate and the subtenant shall peacefully
vacate the premises sublet.

        Section 18.04. Excess Rent. In the event that (i) the total Rentable
Area of the Premises occupied by Tenant or its Permitted Occupants is less than
50% of the Rentable Area of the Premises; and (ii) if the rent agreed upon
between Tenant and its proposed subtenant under any proposed sublease of the
Premises (or any part thereof) is greater than the Rent that Tenant must pay
Landlord hereunder for that portion of the Premises that is subject to such
proposed sublease and at the time of the transaction Tenant is not in Default
hereunder, then one-half of such excess rent (after deducting therefrom the
reasonable costs involved in the transaction, which costs include, without
limitation, brokerage commissions, marketing costs, construction expenses,
tenant concessions, and legal fees) shall be considered Additional Rent owed by
Tenant to Landlord, and shall be paid by Tenant to Landlord in the same manner
that Tenant pays Rent under this Lease. Notwithstanding the foregoing, if at the
time of the assignment or sublease Tenant is in Default hereunder, then until
such Default has been cured by Tenant (i) all such excess rent arising prior to
the cure shall be considered Additional Rent owed by Tenant to Landlord and
shall be paid by Tenant to Landlord in the same manner that Tenant pays Rent
under this Lease, and (ii) all costs associated with the transaction shall be
borne by Tenant and will not be deducted in determining the excess rent payable
to Landlord hereunder.

        Section 18.05. Rights of Landlord. Landlord may sell, transfer, assign,
and convey, all or any part of the Building and/or the Land and any and all of
its rights under this Lease, and in the event Landlord assigns its rights under
this Lease, Landlord shall be released from any further obligations hereunder
which arise after the date of the transfer, and Tenant agrees to look solely to
Landlord's successor in interest for performance of such obligations.




                                      -33-
<PAGE>

        Section 18.06.   Permitted Occupants. Notwithstanding the provisions
of Section 18.01 hereof, Tenant shall have the right, without the prior written
consent of Landlord to assign its entire interest in this Lease to an Affiliate
(hereinafter defined) so long as (i) the Affiliate delivers to Landlord,
concurrently with such assignment, a written notice of the assignment and an
assumption agreement whereby the Affiliate assumes and agrees to perform,
observe and abide by the terms, conditions, obligations and provisions of this
Lease applicable to Tenant and (ii) the entity remains an Affiliate. Further,
Tenant shall also have the right, without the prior written consent of
Landlord, to sublet all or any portion of the Premises to an Affiliate so long
as (i) such sublease is expressly subject to the terms of this Lease so that a
termination of this Lease shall result in the termination of the sublease and
(ii) the entity remains an Affiliate. No assignment or subletting by Tenant
shall relieve Tenant of Tenant's obligations under this Lease. As used herein,
the term Affiliate shall mean and collectively refer to (i) a parent
corporation (the "Parent") of the Tenant which owns and controls not less than
fifty-one percent (51%) of the voting stock of the Tenant and is able to elect
(by ownership of stock or by proxy) the board of directors and the officers of
Tenant, or (ii) a corporation in which either the Tenant or its Parent owns and
controls not less than fifty-one percent (51%) of the voting stock of the
corporation and is able to elect (by ownership of stock or proxy) the board of
directors and the officers of the corporation, or (iii) an Affiliate of the
Parent, and/or (iv) a successor or surviving corporation in the event of a
merger, takeover or other form of corporation acquisition of the Tenant. In
addition to the foregoing, Tenant shall also have the right, without the prior
consent of Landlord, to sublet portions of the Premises to any entity,
organization or individual who is either a contractor or subcontractor of
Tenant or its Affiliate or with whom the Tenant or its Affiliates are a
contractor or subcontractor so long as (i) the terms of the sublease satisfy
the provisions of Section 18.03 hereof and (ii) the total Rentable Area
occupied by such subtenants (or subtenants permitted by Section 18.01 hereof)
does not exceed an aggregate of 50% of the Rentable Area of the Premises. A
transfer permitted under this Section 18.06 will be excluded from the
provisions of Section 18.04 hereof. Entities permitted by this Section 18.06
are collectively referred to as "Permitted Occupants".


                                  ARTICLE 19
                               INDEMNIFICATION


        The Tenant shall indemnify the Landlord and hold the Landlord harmless
from and against all loss or liability for or on account of any injury
(including death) or damage received or sustained by any person or persons
(including the Landlord and any employee, agent or invitee of any of them) to
the extent that such loss or liability is (i) caused by reason or any negligent
act or omission on the part of the Tenant or any employee, representative, or
business visitor of the Tenant and (ii) not covered by insurance maintained by
Landlord pursuant to this Lease.


        The Landlord shall indemnify the Tenant and hold the Tenant harmless
from and against all loss or liability for or on account of any injury
(including death) or damage received or sustained by any person or persons
(including any employee, agent or invitee of the Tenant) to the extent that such
loss or liability is (i) caused by reason of any negligent act or omission on
the part of Landlord or any employee, representative or business visitor of
Landlord and (ii) not covered by insurance maintained by Tenant pursuant to this
Lease.




                                      -34-
<PAGE>

        If either Landlord or Tenant (the "Indemnitee") is made a party to any
litigation commenced against the Indemnitee which falls within the scope of the
foregoing indemnities, then the other party (the "Indemnitor") shall pay all
costs and expenses, including reasonable attorneys, fees and court costs,
incurred by or imposed upon Indemnitee because of any such litigation, and the
amount of such costs and expenses, including reasonable attorneys' fees and
court costs, shall be a demand obligation owing by Indemnitor to Indemnitee.


                                  ARTICLE 20
                          SURRENDER OF THE PREMISES

        Section 20.01. Condition of Premises. Upon expiration of the Term or
other termination of this Lease for any cause whatsoever, Tenant shall
peacefully vacate the Premises in as good order and condition as the same were
at the beginning of the Term or may thereafter have been improved by Landlord or
Tenant, except for reasonable use and wear thereof, and damage to the Premises
or the Leasehold Improvements by fire or other casualty or condemnation.

        Section 20.02. Tenant Holdover. In the event that Tenant shall not
immediately surrender the Premises on the Expiration Date of the Term, Tenant
shall become a month-to-month Tenant subject to all of the terms, conditions,
covenants and agreements of this Lease; however, during the first ninety (90)
days of the holdover Rent will be 125% of the Rent paid during the last month of
the Term; thereafter it will be 150%. However, if Landlord has notified Tenant
that it has relet all or any portion of the Premises and Tenant fails to vacate
the Premises within thirty (30) days after the date of Landlord's notice, then
Tenant shall reimburse Landlord for the costs and damages incurred by Landlord
for failing to deliver the space but in no event will it be greater than 150% of
the Rent. Tenant shall give to Landlord at least thirty (30) days' written
notice of any intention to quit the Premises, and Tenant shall be entitled to
thirty (30) days' written notice to quit the Premises, unless Tenant is in
Default hereunder, in which event Tenant shall not be entitled to any notice to
quit, the usual thirty (30) days written notice being hereby expressly waived.
Notwithstanding the foregoing provisions of this Section, in the event that
Tenant shall hold over after the expiration of the Term, then at any time prior
to Landlord's acceptance of Rent from Tenant as a monthly tenant hereunder,
Landlord, at its option, may forthwith re-enter and take possession of the
Premises without process, or by any legal process in force in the Commonwealth
of Virginia. Tenant shall be liable to Landlord for all damage which Landlord
suffers because of any holding over by Tenant, and Tenant shall indemnify
Landlord against all claims made against Landlord resulting from Landlord's
delay in delivering possession of the Premises to any other tenant or
prospective tenant.


                                  ARTICLE 21
                            ESTOPPEL CERTIFICATES


        Landlord and Tenant each agree that, upon request of a party (the
"Requesting Party"), the other (the "Responding Party") will execute and return,
within fifteen (15) calendar days after the Requesting Party's request, any
certificate that the Requesting Party may request from time to time, stating
that this Lease is unmodified and in full force and effect, or in full force and
effect as modified, and stating the modification. The certificate also shall
state, if true, (i) that all


                                      -35-
<PAGE>

work has been completed, and the work and the Premises are accepted as
satisfactory except for items listed on a punchlist, if any, attached to such
certificate; (ii) the amount of Base Rent and Additional Rent and the dates on
which Rent commenced to accrue and to which the Rent has been paid in advance,
and the amount of any security deposit or prepaid Rent; (iii) that, to the best
of the Responding Party's knowledge, Tenant is in full and complete possession
of the Premises and doing business; (iv) that there is no present default on the
part of the Requesting Party, or attach a memorandum stating any such instance
of default; (v) that the Responding Party has not advanced any amounts to or on
behalf of the Requesting Party which have not been reimbursed; (vi) that, to the
best of Responding Party's knowledge, the Responding Party has no rights to
setoff and no defense or counterclaim against enforcement of its obligations
under the Lease, including the payment of Rent; (vii) that there are no actions,
whether voluntary or otherwise, pending against the Responding Party under the
bankruptcy laws of the United States or any state thereof; and (viii) any other
fact pertaining to this Lease which the Requesting Party may reasonably request.
Failure to deliver the certificate within the fifteen (15) calendar days shall
be conclusive upon the Responding Party for the benefit of the Requesting Party
and its successor that this Lease is in full force and effect and has not been
modified except as may be represented by the party requesting the certificate.


                                  ARTICLE 22
                         SUBORDINATION AND ATTORNMENT

        Section 22.01. Existing Financings.

        (a)     This Lease is subject and subordinate to any deeds of trust or
other security instruments which, as of the date of this Lease, cover the
Building, the underlying land, or any interest of Landlord therein, and to any
advances made on the security thereof, and to any increases, renewals,
modifications, consolidations and extensions of any of such deeds of trust or
security instruments (the "Existing Indebtedness"). This provision is declared
by Landlord and Tenant to be self-operative and no further instrument shall be
required to effect such subordination of this Lease. Upon demand, however,
Tenant shall execute, acknowledge, and deliver to Landlord any further
instruments and certificates evidencing such subordination as Landlord, or the
holder of the Existing Indebtedness may reasonably require.

        (b)     Landlord agrees to obtain from the holder of the Existing
Indebtedness a Subordination, Non-Disturbance and Attornment Agreement, in form
attached hereto as Exhibit "H" (and by this reference incorporated herein),
which provides that, in the event of a foreclosure or a transfer in lieu
thereof, Tenant will not be disturbed in its possession and this Lease shall,
notwithstanding the foreclosure or transfer in lieu thereof, continue in full
force and effect upon and subject to all terms, covenants, conditions, and
obligations of this Lease so long as (i) no Default has occurred on the part of
Tenant under this Lease and (ii) Tenant attorns to the purchaser or transferree
as landlord under this Lease.

        Section 22.02. Future Financings. During the Term of this Lease,
Landlord reserves the right to encumber its interest in this Lease, the Building
and/or the underlying land, by new or additional deeds of trust or other
security instruments and to refinance the Existing Indebtedness




                                      -36-
<PAGE>

(the "New Financing"). Tenant agrees to subordinate this Lease to any New
Financing so long as the holder of the New Financing executes and delivers to
Tenant a Subordination, Non-Disturbance and Attornment Agreement which contains
the provision set forth in Section 22.01(b) hereof and is otherwise a
commercially reasonable instrument.

        Section 22.03. Attornment. Provided the holder of the Existing
Indebtedness and New Financing has delivered to Tenant a Subordination,
Non-Disturbance and Attornment Agreement which satisfies the provisions of
Section 22.01(b) hereof, Tenant shall attorn to the purchaser upon a sale or to
the grantee under any deed in lieu of foreclosure and shall recognize such
purchaser or grantee as Landlord under this Lease without any change in the
terms or other provisions of this Lease. In such agreement, Tenant will waive
the right, if any, to elect to terminate this Lease or to surrender possession
of the Premises in the event of foreclosure of any deed of trust or security
instrument (or any transfer in lieu thereof).

                                  ARTICLE 23
                               QUIET ENJOYMENT


        Provided there is no Event of Default by Tenant of its obligations under
this Lease, Tenant shall, during the Term, peaceably and quietly enjoy the
Premises without disturbance from Landlord or any other persons acting by,
through, or under Landlord; subject, however, to (i) the terms of this Lease;
(ii) the Existing Indebtedness and New Financings (which satisfy the provisions
of Section 22.02 hereof) ordinances, restrictive covenants, leases, easements,
and other agreements or encumbrances now or hereafter affecting the Building or
the land on which the Building is situated; (iii) the right of Landlord to
construct on its property any additional buildings or other improvements now or
hereafter permitted by the governmental authorities having jurisdiction over
Landlord's property; and (iv) the right of Landlord to relocate parking spaces
for the Building, conduct renovations for the Building or make alterations to
the Building so long as Landlord's exercise of the rights reserved under
subparagraphs (iii) and (iv) does not substantially interfere with Tenant's use
of the Premises. This covenant and all other covenants of Landlord in this Lease
shall be binding upon Landlord and its successors only with respect to breaches
occurring during its and their respective ownership of Landlord's interest
hereunder.


                                  ARTICLE 24
                            SIGNS AND FURNISHINGS

        Section 24.01. Signs and Advertisements. No sign, advertisement, or
notice referring to Tenant shall be inscribed, painted, affixed, or otherwise
displayed on any part of the exterior of the Premises or the exterior or the
interior of the Building (if visible to the exterior of the Premises), except
those permitted by Section 24.02 or those installed by Landlord on the
directories and the entrance door to the Premises and such other areas, if any,
as Landlord may determine. Tenant may also install, without the prior consent of
Landlord, locational and directional signage and suite or room numbers within
the Premises so long as the same is not visible to the exterior of the Premises.
If Tenant exhibits or installs any sign, advertisement or notice, without the
prior consent of Landlord, Landlord shall have the right to remove the same at
Tenant's expense.



                                      -37-
<PAGE>

Landlord shall have the right to prohibit any advertisement of or by Tenant
which in its opinion tends to impair the reputation of the Building or its
desirability as a high-quality office building and, upon written notice from
Landlord, Tenant shall immediately refrain from and discontinue any such
advertisement. Landlord reserves the right to affix, install, and display signs,
advertisements, and notices on any part of the exterior or interior of the
Building, however, Landlord's right to install exterior signage for any other
tenant in the Building is subject to the provisions of Section 24.02 hereof.
Landlord shall not, however, have the right to affix upon the exterior of the
Building "for lease" or similar signs advertising the availability of space for
lease in the Building, however, Landlord may utilize monument signage similar to
those in existence for the Building on the date of this Lease.

        Section 24.02. Building Signage.

        (a)     Notwithstanding the provisions of Section 24.01 hereof, Tenant
shall have the right, subject to the provisions of this Section 24.02, to
install, at its sole cost one building identification sign showing the
Tenant's corporate logo. The sign will be located on the roofline of the western
(or I-66) side of the Building. The exact location, size, design, appearance,
and finish of the sign shall be subject to the approval of all applicable
governmental authorities, the Architectural Review Board of Fair Lakes
(established by the Fair Lakes League to which the Building is subject) and
Landlord. Landlord shall use its best efforts to promptly obtain the approval of
the Architectural Review Board of Fair Lakes.

        (b)     Landlord covenants and agrees that, during the Term, no more
than two (2) building identification signs (including the sign erected by Tenant
pursuant to Section 24.02(a)) may be erected upon the exterior of the Building
without the prior consent of Tenant which consent shall not be unreasonably
withheld. Notwithstanding the foregoing, upon the vacation of AETNA Life and
Casualty, as a tenant in the Building, Landlord reserves the right to replace
the Building rooftop sign for AETNA with a sign of a tenant occupying not less
than two floors of the Building or 45,000 square feet of Rentable Area (the
"Other Tenant"), however, (i) the sign of the other Tenant will be removed if
Tenant and its Permitted Occupants occupy 50% or more of the Rentable Area in
the Building or five (5) full floors of the Building, and (ii) Tenant shall have
the only sign along the rooftop of the Building for so long as it and its
Permitted Occupants occupy more than 50% of the Rentable Area in the Building or
five (5) full floors of the Building. Landlord specifically reserves the right,
during foregoing period, to install signage on the exterior of the first floor
of the Building.

        Section 24.03. Furnishings. The Building is designed with a floor load
design capacity of 100 pounds per square foot of live load. In no event shall
Tenant place on any part of the floor of the Premises a load exceeding the
foregoing floor load per square foot and which is allowed by law. Any and all
damage or injury to the Premises or the Building caused by Tenant moving heavy
equipment or fixtures or the same being in or upon the Premises by Tenant, shall
be repaired by and at the sole cost of Tenant. All furniture, equipment, and
other bulky matter of any description shall be delivered to the Premises only
through the designated service entrance of the Building and the designated
service elevator during normal business hours or as otherwise directed or
scheduled by Landlord. All moving of furniture, equipment and other materials
shall


                                      -38-
<PAGE>

be under the supervision of Landlord, who shall not, however, be responsible for
any damage to or charges for moving the same. Tenant agrees to remove promptly
from the sidewalks adjacent to the Building any of Tenant's furniture,
equipment, or other material there delivered or deposited.

        Section 24.04. Satellite Dish.

        (a)     Tenant shall have the right, subject to the provisions of this
Section 24.04, to install, at its sole cost and expense, upon the roof of the
Building a satellite dish antenna. The location of the antenna shall be mutually
agreed upon by Landlord and Tenant prior to the Commencement Date. The size,
design, and appearance of the antenna shall be subject to the approval of all
applicable governmental authorities, the Architectural Review Board of Fair
Lakes and Landlord.

        (b)     In the event that Tenant constructs the antenna then, such
construction shall be subject to all of the provisions of this Lease, including,
but not limited to Article 12 and 13 hereof. Tenant further agrees that the
provisions of Article 19 hereof shall apply to Tenant's use of the roof for the
installation and operation of the antenna. Tenant shall maintain the antenna and
the portion of the roof upon which it is situated in a good, clean and proper
condition and will, at the end of the Term, remove the antenna and restore the
portion of the roof affected thereby as required by Article 12 and 20 hereof.


                                  ARTICLE 25
                            DEFAULTS AND REMEDIES

        Section 25.01. Events of Default. The occurrence of any one or more of
the following events shall constitute a Default or an Event of Default under
this Lease: (a) if Tenant fails to pay any Base Rent, Temporary Rent and/or
Additional Space Rent hereunder as and when the same becomes due and such
failure shall continue for more than fifteen (15) days after Landlord gives
Tenant notice that such payment is past due; (b) if Tenant fails to pay any
installment of Additional Rent hereunder within thirty (30) days after Landlord
gives notice that such payment is due; (c) if Tenant fails to take possession of
either (i) the Phase I Space on the Phase I Rent Commencement Date or promptly
thereafter or (ii) the Phase II Space on the Phase II Rent Commencement Date or
promptly thereafter; (d) if Tenant permits to be done anything which creates a
lien upon the Premises and fails to discharge, or bond such lien or post such
security with Landlord as is required by Article 13; (e) if Tenant violates the
provisions of Article 18 by attempting to make an unpermitted assignment or
sublease; (f) if Tenant fails to maintain in force all policies of insurance
required by this Lease and any such failure shall continue for more than ten
(10) days after Landlord gives Tenant notice of such failure; (g) if any
petition is filed by or against Tenant under any present or future section or
chapter of the Bankruptcy Code, or under any similar law or statute of the
United States or any state thereof (which, in the case of an involuntary
proceeding, is not permanently discharged, dismissed, stayed or vacated, as the
case may be, within ninety (90) days of commencement), or if any order for
relief shall be entered against Tenant in any such proceedings; (h) if Tenant
becomes insolvent or makes a transfer in fraud of creditors or makes an
assignment for the benefit of creditors; (i) if a receiver, custodian, or trus-



                                      -39-
<PAGE>

tee is appointed for the Premises or for all or substantially all of the assets
of Tenant, which appointment is not vacated within ninety (90) days following
the date of such appointment; or (j) if Tenant fails to perform or observe any
other term of this Lease and such failure shall continue for more than thirty
(30) days after Landlord gives Tenant notice of such failure, or, if such
failure cannot be corrected within such thirty (30) day period, if Tenant does
not commence to correct such default within said thirty (30) day period and
thereafter diligently prosecute the correction of same to completion within a
reasonable time and in any event prior to the time a failure to complete such
correction could cause Landlord to be subject to prosecution for violation of
any law, rule, ordinance or regulation or causes, or could cause a default under
any deed of trust, mortgage, underlying lease, Tenant lease or other agreement
applicable to the Project and/or Building.

        Section 25.02. Remedies. Upon the occurrence of any Event of Default,
Landlord shall have the right, at Landlord's option, to terminate this Lease.
With or without terminating this Lease, Landlord may re-enter and take
possession of the Premises and the provisions of this Section 25.02 shall
operate as a notice to quit, any other notice to quit or of Landlord's intention
to reenter the Premises being hereby expressly waived. If necessary, Landlord
may proceed to recover possession of the Premises under and by virtue of the
laws of the Commonwealth of Virginia or by such other proceedings, including
re-entry and possession, as may be applicable. If Landlord elects to terminate
this Lease, everything contained in this Lease on the part of Landlord to be
done and performed shall cease without prejudice; subject however, to the right
of Landlord to recover from Tenant all rent and other sums accrued up to the
time of termination or recovery of possession by Landlord, whichever is later.
Whether or not this Lease is terminated by reason of Tenant's Default, Landlord
may, but shall not be obligated to, relet the Premises for such rent and upon
such terms as are not unreasonable under the circumstances and, if the entire
Rent provided in this Lease plus the costs, expense, and damages hereafter
described shall not be realized by Landlord, Tenant shall be liable for all
damages sustained by Landlord, including, without limitation, attorney's fees
and expenses reasonably incurred, brokerage fees, and the expense of placing the
Premises in first-class rentable condition. Landlord shall in no way be
responsible or liable for any failure to collect any rent due and/or accrued
from such reletting, to the end and intent that Landlord may elect to hold
Tenant liable for the Rent which Tenant shall have been obligated to pay
throughout the remainder of the Term. Landlord shall, however, use reasonable
efforts to relet the Premises and mitigate its damages. Any damages or loss of
rent sustained by Landlord may be recovered by Landlord, at Landlord's option,
at the time of the reletting or in separate actions, from time to time, as said
damage shall have been made more easily ascertainable by successive relettings,
or, at Landlord's option, may be deferred until the expiration of the Term, in
which event Tenant hereby agrees that the cause of action shall not be deemed to
have accrued until the date of Expiration of the Term. In the event such damages
or loss of rent are recovered at the time of the reletting and the judgment
rendered in Landlord's favor requires the Tenant to pay for future losses
suffered by the Landlord, Tenant shall be liable for an amount equal to the
present value (as of the date of the judgment for Landlord) of the Rent which
would have been paid by Tenant for the remaining balance of the Term, but for
Tenant's Default, less the present value (as of the date of the judgment for
Landlord) of the revenue stream Landlord reasonably expects to receive over the
remainder of the Term as a result of the reletting of the Premises. For purposes
of the foregoing sentence, present value shall be determined by


                                      -40-
<PAGE>

discounting at a rate equal to one and one-half percentage points above the
discount rate then in effect at the Federal Reserve Bank nearest to the
Building. There shall be no discounting for present value for any judgment which
covers losses incurred by Landlord prior to the reletting or portions of the
award applicable to sums accruing prior to the date of the judgment. The
provisions contained in this Section 25.02 shall be in addition to, and shall
not prevent the enforcement of, any claim Landlord may have against Tenant for
anticipatory breach of this Lease.

        Section 25.03. Remedies Cumulative. All rights and remedies of Landlord
set forth herein are in addition to all other rights and remedies available to
Landlord at law or in equity. All rights and remedies available to Landlord
hereunder or at law or in equity are expressly declared to be cumulative. The
exercise by Landlord of any such right or remedy shall not prevent the
concurrent or subsequent exercise of any such right or remedy. No delay in the
enforcement or exercise of any right or remedy granted Landlord or Tenant under
this Lease shall constitute a waiver of any Default by the defaulting party
hereunder or of any rights or remedies in connection therewith available
hereunder to the non-defaulting party. No party shall be deemed to have waived
any Default by the other hereunder unless such waiver is set forth in a written
instrument signed by the party against the waiver is asserted. Any waiver in
writing shall be limited to its terms and shall not be construed as a waiver of
any covenant, condition, or agreement set forth in this Lease except as to the
specific circumstances described in such written waiver.

        Section 25.04. No Acceptance or Surrender. No act or thing done by
Landlord or its agents during the Term shall constitute an acceptance of an
attempted surrender of the Premises, and no agreement to accept a surrender of
the Premises shall be valid unless made in writing and signed by Landlord. No
re-entry or taking possession of the Premises by Landlord shall constitute an
election by Landlord to terminate this Lease, unless a written notice of such
intention is given to Tenant. Notwithstanding any such reletting or re-entry or
taking possession, Landlord may at any time thereafter terminate this Lease for
a previous Default. Landlord's acceptance of Rent following an Event of Default
hereunder shall not be construed as a waiver of such Event of Default unless the
payment cures such Event of Default.

        Section 25.05. Customs and Practices. No custom or practice which may
develop between the parties in the administration of the terms of this Lease
shall be construed to waive or lessen a party's right to insist upon strict
performance of the terms of this Lease.

        Section 25.06. Payment of Tenant's Obligations by Landlord. In the Event
of Default, Landlord may, but shall not be required to, make such payment or do
such act required to be performed by Tenant. If Tenant fails to act and Landlord
makes such payment or does such act, all costs and expenses incurred by
Landlord, plus interest thereon at the rate per annum which is two percent (2%)
higher than the "prime rate" published in the Money Rates section of the Wall
Street Journal (the "Default Rate"), from the date paid by Landlord to the date
of payment thereof by Tenant, shall be immediately paid by Tenant to Landlord;
provided, however, that nothing contained therein shall be construed as
permitting Landlord to charge or receive interest in excess of the maximum legal
rate then allowed by law. The taking of such action by Landlord shall not be
considered as a cure of such Default by Tenant or to prevent Landlord from
pursuing any remedy it is otherwise entitled to in connection with such Default.



                                      -41-
<PAGE>

        Section 25.07. Default by Landlord. Should Landlord breach any of its
warranties or representations herein set forth or fail to perform any of its
covenants herein contained, Tenant shall notify Landlord of such default or
breach and Landlord shall have a period of 30 days after receipt of written
notice to remedy such breach or default, except in an emergency or life
threatening situation, in which case Landlord shall have a reasonable period to
cure such situation. If such breach or default cannot be cured within such
period, Landlord shall have such additional period that shall be reasonably
necessary to remedy such breach or default provided that Landlord is diligently
and continuously pursuing such remedy and provided further that Tenant is not
materially damaged or prejudiced. Should Landlord fail to cure such breach or
default, Tenant shall have available to it the following remedies, as its sole
and exclusive remedies, Tenant specifically waiving any other remedy it may have
at law or at equity:

        (a)     Terminate this Lease in the event of a material default which
renders it reasonably impracticable to occupy the Premises;

        (b)     Bring suit against Landlord for specific performance;

        (c)     Pursue any other rights and remedies specifically granted to
Tenant hereunder; or

        (d)     For so long as Tenant or its Permitted Occupants are occupying
not less than 40% of the Rentable Area of the Building, if such breach or
default is under the provisions of Sections 7.01, 7.04 and 14.02 hereof or
Articles 8, 16 or 17 hereof, then Tenant shall have the right to cure such
breach or default only to the extent that it affects the Premises. In the event
that Tenant elects to exercise its rights under subparagraph (d), then the
following provisions shall apply:

        (i)     Tenant shall diligently and continuously pursue such cure until
                the default or breach is corrected;

        (ii)    Tenant shall perform such cure in a manner which, to the extent
                reasonably practicable, minimizes interference or disruption to
                the other tenants of the Building;

        (iii)   All such work shall be performed using firstclass materials, in
                a good and workmanlike manner consistent with all applicable
                governmental requirements;

        (iv)    Should Tenant be required to expend funds in its cure of the
                Landlord's breach of default, then all costs and expenses
                incurred by Tenant shall be due and payable by Landlord within
                fifteen (15) days of a receipt of written demand from Tenant for
                such payment accompanied by a reasonably detailed statement of
                expenditures together with invoices shall bear interest at the
                Default Rate, from the date paid by Tenant to the date of
                payment thereof by Landlord. In the event that such sum (and
                interest accruing thereon) is not paid within sixty (60) days
                after receipt of written demand from Tenant, then Tenant may
                deduct such amount (and interest accrued thereon) against the
                installments of Rent until paid in full.


        Tenant agrees to give written notice of any default by Landlord under
this Lease to any lender of Landlord secured by the Premises upon request
thereof by such lender and a reasonable


                                      -42-
<PAGE>

time within which to cure such default prior to Tenant taking any action to
remedy such default or cancel the Lease.


                                  ARTICLE 26
                               SECURITY DEPOSIT


        (a)     In the event Tenant desires to assign its interest in the Lease
and be relieved of continuing liability hereunder, Landlord may require, as a
condition to its consent to any such assignment, that the assignee posts a
security deposit (the "Security Deposit") equal to one (1) month Rent due under
the Lease at the time of the Assignment.

        (b)     The Security Deposit shall be security for the performance by
Tenant of all of Tenant's obligations, covenants, conditions, and agreements
under this Lease. Within thirty (30) days after the expiration of the Term, and
provided Tenant has vacated the Premises and is not in Default hereunder,
Landlord shall return the Security Deposit to Tenant, less such portion thereof
as Landlord shall have appropriated to satisfy any Default by Tenant hereunder.
In the event of any default by Tenant hereunder, Landlord shall have the right,
but shall not be obligated to use, apply or retain all or any portion of the
Security Deposit for (i) the payment of any Rent to which Tenant is in Default,
(ii) the payment of any amount which Landlord may spend or become obligated to
spend by reason of Tenant's Default, or (iii) the payment of any amount Landlord
may spend or become obligated to spend or for compensation of Landlord for any
losses incurred by reason of Tenant's Default, including, but not limited to,
any damage or deficiency arising in connection with the reletting of the
Premises. If any portion of the Security Deposit is so used or applied, within
three (3) business days after written notice to Tenant of such use or
application, Tenant shall deposit with Landlord an amount sufficient to restore
the Security Deposit to its original amount, and Tenant's failure to do so shall
constitute a Default under this Lease.


                                  ARTICLE 27
                            INTENTIONALLY OMITTED


                                  ARTICLE 28
                      ATTORNEY'S FEES AND LEGAL EXPENSES


        In any action or proceeding brought by either party against the other
under this Lease, the prevailing party shall be entitled to recover from the
other party reasonable attorneys' fees, and other reasonable legal expenses and
court costs incurred by such party in such action or proceeding as the court may
find to be reasonable.


                                  ARTICLE 29
                                   NOTICES


        Any notice or document required to be delivered hereunder shall be in
writing and shall be given or made or communicated by United States registered
or certified mail or by any overnight or express mail service which provides
receipts to indicate delivery, addressed to the parties hereto at the respective
addresses as specified in the Basic Lease Information, or at such other
addresses they have subsequently specified by written notice.


                                      -43-
<PAGE>

        All notices shall be effective upon being deposited in the manner
prescribed above, however, the time period in which a response to such notice
must be given shall commence to run from the date of receipt by the addressee
thereof as shown on the return receipt of the notice. Rejection or other refusal
to accept or the inability to deliver because of changed address of which no
notice was given, shall be deemed to be receipt of the notice as of the date of
such rejection, refusal or inability to deliver.


                                  ARTICLE 30
                            RIGHT OF FIRST REFUSAL


        Provided Tenant is not in Default under this Lease at the applicable
time, Tenant, during the Refusal Period (hereinafter defined), shall, in the
manner described by and in compliance with the terms and provision of this
Article 30 have a right of first refusal to expand the Premises to include all
or any portion of the Additional Space (hereinafter defined).

        (a)     If at any time during the Refusal Period Landlord shall either
(i) receive a bonafide offer from a third party to lease all or a portion of the
Additional Space, which Landlord is prepared to accept, or (ii) prepares a
proposal pertaining to all or a portion of the Additional Space which Landlord
is prepared to offer as a lease proposal to a third party, then in either such
event, landlord shall send a written notice (the "Offer Notice") to Tenant of
such proposal. The Offer Notice shall set forth in reasonable detail the size or
portion of the Additional Space subject to the Offer Notice, and shall contain
(or be deemed to contain) an offer to Tenant to lease the portion of the
Additional Space subject to the Offer Notice for the remaining Term of this
Lease on the same terms and conditions set forth in the Offer Notice. (Except
that the concessions offered to the third party pursuant to the proposal forming
the basis of the Offer Notice shall be appropriately prorated if the remaining
Term of this Lease is shorter than the term contemplated by the proposal forming
the basis of the Offer Notice.) Tenant may elect to accept the Offer Notice, by
giving written notice to Landlord of its election not less than ten (10) days
after receipt by Tenant of the Offer Notice.

        (b)     In the event Tenant responds within the ten (10) day period and
elects to accept the proposal set forth in the Offer Notice, then this Lease
shall automatically be amended to include within the Premises the portion of the
Additional Space subject to the Offer Notice. The rent payable for the
Additional Space subject to the Offer Notice (the "Additional Space Rent") will
be as set forth in the Office Notice and Tenant will be entitled to all rental
concessions set forth in the Offer Notice prorated as set forth in subparagraph
(a) hereof. Tenant will take the space subject to the Offer Notice in its "as
is" and "where as" condition, however, Landlord will (i) perform in the
Additional Space all work required by the Offer Notice; (ii) grant to Tenant any
construction allowances that may be set forth in the Offer Notice prorated as
set forth in subparagraph (a) hereof; and (iii) deliver such space upon
Substantial Completion of all improvements thereto. The provisions of this
subparagraph shall be self-enforcing without the need for any further act by
Landlord or Tenant.

        (c)     Should Tenant either fail to respond within the ten (10) days,
or elects not to accept the Offer Notice, then the Landlord shall be free to
execute a lease (the "Space Lease") for


                                      -44-
<PAGE>

the portion of the Additional Space subject to the Offer Notice on terms not
materially different than those set forth in the Offer Notice and thereupon such
space shall be automatically excluded from the Additional Space and the rights
of Tenant set forth in this Article, as they pertain to the portion of the
Additional Space which is subject to the Offer Notice, shall automatically
terminate and be of no further force or effect. The provisions of this
subparagraph shall be self-enforcing without the need for any further act by
Landlord or Tenant.

        (d)     Notwithstanding the foregoing provisions of subparagraph (c)
hereof, should Tenant either fail to respond within ten (10) days, or elects not
to accept the Offer Notice, then the portion of the Additional Space subject to
the Offer Notice shall again become a part of the Additional Space subject to
the provisions of this Article upon either (i) the expiration or termination of
the Space Lease or (ii) six (6) months after the date of an Offer Notice if
Landlord is unable, within such period of time, to execute a Space Lease for the
space subject to the Offer Notice.

        (e)     An election by Tenant under this Article shall be irrevocable.

        (f)     As used herein, the term "Refusal Period" shall mean and refer
to the period commencing on the Commencement Date and expiring upon the earlier
of (i) the date on which Tenant's rights under this Article with respect to the
Additional Space are terminated pursuant to subparagraphs (b) and (c) hereof or
(ii) the commencement of the last year of the Term of this Lease (as it may be
extended by the Renewal Terms).

        (g)     As used herein, the term "Additional Space" shall mean and refer
to all of the Rentable Area of the Building excluding the Premises.

        (h)     The rights granted Tenant hereunder are subject to the rights
granted to others pursuant to leases in effect in the Building as of the date
hereof.


                                  ARTICLE 31
                                MISCELLANEOUS

        Section 31.01. No Partnership. Nothing contained in this Lease shall be
construed as creating a partnership or joint venture of or between Landlord and
Tenant, or to create any other relationship between the parties hereto other
than that of Landlord and Tenant.

        Section 31.02. Brokers. Landlord recognizes the Broker as the Broker
under this Lease and shall pay the Broker a commission pursuant to a separate
agreement between the Landlord and Broker. Landlord and Tenant each represent
and warrant to the other that, except as provided above, neither of them has
employed or dealt with any broker, agent or finder in carrying on the
negotiations relating to this Lease. In the event of a breach by a party of
their foregoing representation and warranty (the "Defaulting Party"), the
Defaulting Party shall indemnify and hold the other party harmless from and
against any claim or claims, damages or expenses (including any claims for
brokerage or other commissions asserted by broker, agent or finder fees) which
may arise as a result of such breach.


                                      -45-
<PAGE>

        Section 31.03. Severability. Every agreement contained in this Lease is,
and shall be construed as, a separate and independent agreement. If any term of
this Lease or the application thereof to any person or circumstances shall be
invalid and unenforceable, the remainder of this Lease, or the application of
such term to persons or circumstances other than those as to which it is invalid
or unenforceable, shall not be affected.

        Section 31.04. Trial by Jury. Landlord and Tenant each hereby waive
trial by jury in any action, proceeding or counterclaim brought by either of
them against the other in connection with any matter arising out of or in any
way connected with this Lease, the relationship of landlord and tenant
hereunder, Tenant's use or occupancy of the Premises, or any claim of injury or
damage.

        Section 31.05. Force Majeure. Whenever a period of time is herein
prescribed for action to be taken by a party, the party shall not be liable or
responsible for, and there shall be excluded from the computation for any such
period of time, any delays due to strikes, riots, acts of God, shortages of
labor or materials, war, governmental laws, regulations, or restrictions, or any
other cause of any kind whatsoever which is beyond the reasonable control the
party. However, the failure or inability to obtain or have funds required for a
performance of a parties, obligation shall not be a basis of force majeure.
Force Majeure shall not be applicable to Tenant's obligation to pay Rent
hereunder as and when it is due and payable.

        Section 31.06. Captions. The article and section headings contained in
this Lease are for convenience only and shall not enlarge or limit the scope or
meaning of the provisions hereof. Words of any gender used in this Lease shall
include any other gender, and words in the singular number shall be held to
include the plural, unless the context otherwise requires.

        Section 31.07. Benefit and Burden. If there be more than one Tenant, the
obligations hereunder imposed upon Tenant shall be joint and several, and all
agreements and covenants herein contained shall be binding upon their respective
heirs, personal representatives, successors, and, to the extent permitted under
this Lease, assigns of the parties hereto. If there be more than one Landlord,
the obligations hereunder imposed upon Landlord shall be joint and several, and
all agreements and covenants herein contained shall be binding upon respective
heirs, personal representatives, successors, and assigns.

        Section 31.08. No Representations by Landlord. Neither Landlord nor
Landlord's agents or brokers have made any representations or promises with
respect to the Premises or the Building except as herein expressly set forth and
all reliance with respect to any representations or promises is based solely on
those contained herein. No rights, easements, or licenses are acquired by Tenant
under this Lease by implication or otherwise except as expressly set forth in
this Lease.

        Section 31.09. Entire Agreement. This Lease sets forth the entire
agreement between the parties and cancels all prior negotiations, arrangements,
brochures, agreements, and understandings, if any, between Landlord and Tenant
regarding the subject matter of this Lease. No amendment or modification of this
Lease shall be binding or valid unless expressed in a writing executed by both
parties hereto.



                                      -46-
<PAGE>

        Section 31.10. No Offer. The submission of this Lease to Tenant shall
not be construed as an offer, nor shall Tenant have any rights with respect
thereto unless Landlord executes a copy of this Lease and delivers the same to
Tenant.


        Section 31.11. Authority. If Tenant signs as a corporation, each of the
persons executing this Lease on behalf of Tenant represents and warrants that
Tenant is a duly organized and existing corporation, that Tenant has been and is
qualified to do business in the Commonwealth of Virginia, that the corporation
has full right and authority to enter into this Lease, and that all persons
signing on behalf of the corporation were authorized to do so by appropriate
corporate actions. If Tenant signs as a partnership, trust, or other legal
entity, each of the persons executing this Lease on behalf of Tenant represents
and warrants that Tenant has complied with all applicable laws, rules, and
governmental regulations relative to its right to do business in the
Commonwealth of Virginia, that such entity has the full right and authority to
enter into this Lease, and that all persons signing on behalf of the Tenant were
authorized to do so by any and all necessary or appropriate partnership, trust,
or other actions.


        If Landlord signs as a corporation, each of the persons executing this
Lease on behalf of Landlord represents and warrants that Landlord is a duly
organized and existing corporation, that Landlord has been and is qualified to
do business in the Commonwealth of Virginia, that the corporation has full right
and authority to enter into this Lease, and that all persons signing on behalf
of the corporation were authorized to do so by appropriate corporate actions. If
Landlord signs as a partnership, trust, or other legal entity, each of the
persons executing this Lease on behalf of Landlord represents and warrants that
Landlord has complied with all applicable laws, rules, and governmental
regulations relative to its right to do business in the Commonwealth of
Virginia, that such entity has the full right and authority to enter into this
Lease, and that all persons signing on behalf of the Landlord were authorized to
do so by any and all necessary or appropriate partnership, trust, or other
actions.


        Section 31.12. Changes Requested by Lender. If, in connection with
obtaining financing for the Building, any lender shall request reasonable
modifications in this Lease as a condition for such financing, Tenant will not
unreasonably withhold, delay, or defer its consent thereto, provided that such
modifications do not increase the obligations of Tenant hereunder or diminish
Tenant's rights hereunder or materially adversely affect either the leasehold
interest hereby created or Tenant's use and enjoyment of the Premises.


        Section 31.13. Governing Law and Construction. This Lease shall be
governed by and construed under the laws of the Commonwealth of Virginia.
Printed parts of this Lease shall be as binding on a parties hereto as other
parts hereof. Parts of this Lease which are written or typewritten shall have no
greater force or effect than, and shall not control, parts which are printed,
but all parts shall be given equal effect. Tenant declares that Tenant has read
and understands all parts of this Lease, including all printed parts thereof.
Should any provision of this Lease require judicial interpretation, it is agreed
that the court interpreting or considering same shall not apply the presumption
that the terms hereof shall be more strictly construed against a party by reason
of the rule or conclusion that a document should be construed more strictly
against the party who itself or through its agent prepared the same, it being
agreed that all parties


                                      -47-
<PAGE>

hereto have participated in the preparation of this Lease and that legal counsel
was consulted by each party hereto before the execution of this Lease.


        Section 31.14. Exhibits. The Exhibits referred to in the Basic Lease
Information are by this reference incorporated fully herein. The term "this
Lease" shall be considered to include all such Exhibits.


        Section 31.15. Landlord's Liability. Anything contained in this Lease to
the contrary notwithstanding, Tenant agrees that Tenant shall look solely to the
estate and property of Landlord in the Building and the land upon which is
situated for the collection of any judgment or other judicial process requiring
the payment of money by Landlord for any default or breach by Landlord under
this Lease, subject, however, to the prior rights of any mortgagee or lessor of
the Building and land upon which the Building is situated. No other assets of
Landlord or any partners, shareholders, or other principals of Landlord shall be
subject to levy, execution or other judicial process for the satisfaction of
Tenant's claim.


        Section 31.16. Use of Name of Building. Tenant shall not, without prior
written consent of Landlord, use the name of the Building for any purpose other
than as the address of the business to be conducted by Tenant on the Premises,
and Tenant shall not-do or permit the doing of anything in connection with
Tenant's business or advertising which in the reasonable judgment of Landlord
may reflect unfavorably on Landlord or the Building or confuse or mislead the
public as to any apparent connection or relationship between Tenant and
Landlord, the Building or the land upon which it is situated.


        Section 31.17. Time of Essence. Time is of the essence in this Lease for
the Landlord and Tenant.


        EXECUTED as of the date first written above.


                       LANDLORD:


                       HYATT PLAZA LIMITED PARTNERSHIP
                       a Virginia limited partnership


                       By:   Fair Lakes Hyatt Limited Partnership, a
                             Virginia limited partnership, its general partner


                             By:   Fair Lakes of Virginia, Inc.
                                   a Virginia corporation


                             By:        [SIG]
                                  -----------


                             Its:
                                  -------------------------------------







                                    TENANT:



                                      -48-
<PAGE>

                                    AMERICAN MANAGEMENT SYSTEMS, INC.
                                    a Delaware corporation


                                    By:   /s/ Frank A. Nicolai
                                    -------------------------------------


                                    Its:  Exec. VP, Secretary & Treasurer
                                    -------------------------------------


[THE FOLLOWING PAGES INCLUDE AS EXHIBIT A FLOOR PLANS OF THE PREMISES.]






                                      -49-
<PAGE>




                              EXHIBIT "B" TO LEASE


                             DATED AUGUST 12, 1993


                                    BETWEEN


                        HYATT PLAZA LIMITED PARTNERSHIP
                   A VIRGINIA LIMITED PARTNERSHIP, (LANDLORD)


                                      AND


                       AMERICAN MANAGEMENT SYSTEMS, INC.
                            A CORPORATION, (TENANT)


                             LEASEHOLD IMPROVEMENTS


        This Exhibit "B" is attached to and made a part of that certain Office
Lease Agreement dated August 12, 1993 (the "Lease"), between HYATT PLAZA LIMITED
PARTNERSHIP ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC. ("Tenant"). The
terms used in this Exhibit that are defined in the Lease shall have the same
meanings as provided in the Lease.


        The purpose of this Exhibit "B" is to set forth the relative rights and
obligations of Landlord and Tenant with respect to the construction and
installation of the initial tenant improvements in the Premises.

A.      DEFINITIONS

        1. "Existing Improvements" means all improvements existing in the
Premises that are more particularly shown on Exhibit B Schedule 1 attached
hereto and incorporated herein.

        2. "Contractor" means the person or firm from time to time selected by
Tenant (pursuant to Paragraph D(3) hereof) to install the Leasehold Improvements
in the Premises.

        3. "Leasehold Improvements" shall mean the aggregate of improvements to
the Premises required by the Approved Plan.

        4. "Tenant's Architect" shall mean the architect or space planner
designated by Tenant and approved by Landlord to prepare the plans and
specifications for the Leasehold Improvements.

        5. "Approved Plan" shall mean the plan for Leasehold Improvements
approved by Landlord and Tenant pursuant to Paragraph D.4. hereof.

B.      GENERAL PROVISIONS

        1. Unless otherwise agreed to in writing by Landlord and Tenant, all
work involved in the design and construction of the Leasehold Improvements shall
be carried out by Tenant, Tenant's Architect and Tenant's Contractor. Each party
shall cooperate with the other to promote the



                                      B-1
<PAGE>

efficient and expeditious completion of such work so that occupancy of each
phase of the Premises may occur when required by Section 3.01 of the Lease.

        2. As of the date of execution of this Lease, the Premises are improved
with the Existing Improvements. All costs associated with the design and
construction of the Premises pursuant to an Approved Plan (including any
demolition to the Existing Improvements) shall be borne by Tenant. As more
particularly set forth in the Lease, Landlord has granted to Tenant a Tenant
Allowance. The Tenant Allowance will be made available to Tenant in monthly
installments. Tenant shall, on a monthly basis, submit to Landlord a statement
setting forth the expenditures made by Tenant during the preceding month with
respect to the Leasehold Improvements. The statement shall be accompanied by
lien waivers from persons paid during the previous month and invoices or
receipts evidencing the amount Tenant has requested Landlord to disburse from
the Tenant Allowance. In such monthly statement, Tenant shall designate which
payments it desires the Landlord to make directly to the billing party. Provided
there is no Event of Default, Landlord shall, within ten (10) days after its
receipt of Tenant's monthly statement, disburse the amount requested. Should the
cost of the Leasehold Improvements exceed the Tenant Allowance, then such excess
shall be paid by Tenant.

C.      DESIGN

        1. Tenant may draw from the Tenant Allowance the cost of all design
services (including all necessary architectural, mechanical and electrical
drawings) required for the Approved Plan.

        2. The design, construction, and installation of the Leasehold
Improvements shall conform to the requirements of applicable building, plumbing,
and electrical codes and the requirements of any authority having jurisdiction
over, or with respect to, such work.

        3. All architectural, mechanical, and electrical plans and
specifications for the Leasehold Improvements must be approved by Landlord. Any
changes in the Approved Plans must also be approved by Landlord. Tenant shall
not be permitted to modify the Building in any way, including but not limited to
the structural, mechanical, and electrical systems, except as approved by
Landlord on the Approved Plan. No alterations by Tenant to the Leasehold
Improvements shall be allowed at any time except as provided in the Lease.

D.      PROCEDURES FOR COMPLETION OF LEASEHOLD IMPROVEMENTS


        The following procedures shall be followed in completing the Leasehold
Improvements.

        1. Prior to commencing construction of any Phase, Tenant shall prepare
and submit to Landlord (for its information) a construction schedule.

        2. Tenant's Architect shall complete working drawings and specifications
and submit the same to Tenant and Landlord approval. Within five (5) business
days after their receipt of such working drawings and specifi-


                                      B-2
<PAGE>

cations, each party shall notify the Tenant's Architect and the other party in
writing as to whether it approves or disapproves such working drawings and
specifications. Should the working drawings and specifications (or parts
thereof) be disapproved by either party, the party, in its notice of
disapproval, shall specify, in reasonable detail, the reasons for its
disapproval. The Tenant's Architect will revise the material and resubmit the
same to Landlord and Tenant for their review and approval. Within five (5) days
after their receipt of the revised material, each party shall notify the other
and the Tenant's Architect in writing as to whether it approves or disapproves
of the revised material. The foregoing process will be repeated (within the time
periods permitted) until such time as both Landlord and Tenant have approved the
working drawings and specifications. Upon approval of the working drawings and
specifications, they will be deemed to be the "Approved Plan" for the phase in
question.

        3. Tenant shall select the general contractor (the "Contractor") who
will perform the Leasehold Improvements. Tenant's selection of the Contractor
shall be subject to Landlord's written approval, which approval shall not be
unreasonably withheld, conditioned or delayed.

E.      RIGHT AND OBLIGATIONS OF LANDLORD

        1. Landlord is permitted to make periodic inspections of the Premises
during construction provided that such inspections are made during reasonable
business hours. Tenant shall not be liable for any damage or injury sustained by
Landlord, or any of Landlord's agents, representatives or employees arising from
Landlord's entry upon the Premises during the construction of the Leasehold
Improvements.

        2. Whenever this Exhibit requires an act by Tenant or a plan, contract
or other construction related document related to the Leasehold Improvements
(the "Construction Document"), to be approved by Landlord, such approval shall
not be unreasonably withheld, conditioned or delayed. The failure of Landlord to
notify Tenant within the time period specified (or if no period is specified
within five (5) business days after Tenant's request for Landlord's approval),
shall constitute Landlord's approval of the Construction Document in question.
Whenever Landlord withholds its approval, Landlord shall provide Tenant with an
explanation of why the approval is being withheld and/or what corrective actions
must be taken so that Landlord may approve the Construction Document in
question. Each party agrees to use good faith efforts to resolve any conflict or
disagreement.

F.      TENANT'S RIGHTS


        In its performance of the Leasehold Improvements, Tenant shall have the
right to take such actions and utilize such facilities as are customarily and
reasonably taken and utilized in the construction of comparable space, subject
to such customary and reasonable restrictions as Landlord may adopt in the
prudent management of the Building. Tenant shall not be charged for the use of
utilities, elevators, loading docks, and similar Building facilities in the
construction of the Leasehold Improvements. No fees of any manner shall be
charged by Landlord for its review of plans and drawings or any supervision or
inspection of the Leasehold Improvements. Landlord shall cause any of its
contractors working in the Building to work in harmony with Tenant and the
Contractor, and Landlord shall not knowingly permit any other contractors to
interfere with the performance of the Leasehold Improvements.


                                      B-3
<PAGE>




        [THE DOCUMENT INCLUDES AS EXHIBIT C A SQUARE FOOT CHART SHOWING VARIOUS
MEASURES OF USABLE SPACE ON EACH FLOOR.]






                                      B-4
<PAGE>



                              EXHIBIT "D" TO LEASE


                             DATED August 12, 1993


                                    BETWEEN


                   HYATT PLAZA LIMITED PARTNERSHIP (Landlord)


                                      and


                       AMERICAN MANAGEMENT SYSTEMS, INC.


                                    (Tenant)


                            CLEANING SPECIFICATIONS


SPECIFICATIONS


AREAS:      The entire premises, including all office space, entrance
            lobby(ies), basement areas, loading platforms), receiving areas,
            landings/steps, public halls, stairways, lavatories, passageways
            and elevator cabs.


PART A - DAILY SERVICES


1.    Toilet Rooms


Rest rooms are to receive complete cleaning and sanitation each night
according to the specifications listed below:

a.      Commodes and Urinals: Commodes shall be washed inside and outside
        including under the lips of each bowl. All seats shall be washed. This
        work shall be performed using an approved disinfectant cleanser. All
        bright metal shall be cleaned and, dry polished. Deodorant blocks shall
        not be used in the urinals.

b.      Washbasins: Washbasins shall be washed inside and outside using an
        approved disinfectant cleanser. All bright metal fixture units and
        plumbing shall be dry polished.

c.      Stall Partitions: All stall partitions shall be damp cleaned using an
        approved disinfectant cleanser. Special attention shall be given to
        urinal partitions.

d.      Entrance Doors: All entrance doors, including stops, jambs, and frames
        shall be cleaned.

e.      Mirrors and Lights: All mirrors and lights immediately above mirrors
        shall be cleaned. Burned out lights shall be reported to the maintenance
        department.

f.      Couches and Chairs: Lather or vinyl couches and chairs shall be damp
        cleaned. All vanity chairs, stools and other furniture shall be treated
        in a like manner.

                                      D-1
<PAGE>

g.      Sanitary Napkin Disposal Containers: All sanitary napkin containers
        shall be emptied, damp cleaned with an approved disinfectant cleanser
        and provided with a new paper bag liner daily.

h.      Installation of Supplies: All supplies such as toilet tissue, paper
        towels, liquid hand soap and bar soap is to be replenished. Insure that
        proper liquid soap is used in dispensers to avoid malfunction (dilute
        with water if necessary to prevent clogging). Periodically, clean
        operating mechanisms and replace liquid soap supply in each dispenser to
        insure proper operation.

i.      Mosaic Floors:    -     Pick up loose paper and trash
                          -     Sweep all floors
                          -     Wet mop floors, using an approved disinfectant
                                cleanser

j.      Walls: Wash/clean walls around soap dispensers, towel containers, and
        light switches as required to maintain clean/bright appearance.

k.      Traps and Floor Drains: Shall be maintained free from odor at all times.
        Periodically, water shall be poured down through these traps/floor
        drains to insure vapor seal.


NOTE:   No harsh or abrasive cleaner shall be used without consulting the
        Property Manager.


2.      Room Cleaning


Executive Offices - Private Offices - Semi-Private Offices -
Reception Areas - Conference Rooms - General Offices


The areas stated above are to receive complete general cleaning daily
according to the specifications listed below.


a.      Wastepaper and Trash Containers: All trash containers shall be emptied
        and returned to original locations. Plastic liners shall be used in
        trash containers and changed as necessary for appearance and sanitation.
        Trash containers shall be periodically washed, for appearance and
        sanitation. All trash collected shall be deposited in exterior bulk
        trash containers provided by the Property Manager. Doors on these
        containers shall be kept closed when not in use. Any spills occurring
        during emptying of trash shall be cleaned up immediately (inside or
        outside), and related stains shall be washed/shampooed as required.

b.      Entrances to Executive Offices and Entrances to of Office Areas on
        Various Floors: All glass doors, plate glass side panels and mirrors,
        including metal frames, stops, jambs shall be cleaned as necessary.

c.      Ash Trays: All ash trays shall be emptied. Ash trays shall then be wiped
        clean with a damp cloth to remove stains and odors.

                                      D-2
<PAGE>

d.      Desks and Chairs: Wood desks shall be thoroughly dusted with a treated
        dust cloth and oiled/waxed as required. Metal desks shall be damp wiped
        as necessary to remove spots and stains, including front and side
        vertical surfaces. All glass desk tops will be damp cleaned. Papers on
        desks shall not be disturbed. All chairs shall be dusted or vacuumed
        from top to bottom, as required.

e.      File and Storage Cabinets: All file and storage cabinets shall be
        thoroughly dusted with a treated dust cloth. Cabinets lined in a row
        shall be dusted along the horizontal and vertical surface of each
        cabinet. Spill stains shall be damp cleaned when required.

f.      Tables and Lamps: Tables shall be treated in a like manner as desks.
        Lamps shall be dusted thoroughly, using a treated dust cloth. When
        dusting lamp shades, be certain that cloth is not laden with dust. Cloth
        lamp shades shall be vacuumed with a soft brush type tool.

g.      Hand Dust/Clean the following using a treated dust cloth:

        -  Window Sills
        -  Pictures and Frames
        -  Counters
        -  Radiator and Fan Coil Unit enclosures (damp clean as required)
        -  Ledges and Shelves under six feet
        -  Doors, Jambs and Stops (particularly along top/horizontal surface)
        -  Pushplates and Kickplates
        -  Coat rack and trees
        -  Telephones, all types including office and telephones in booths
        -  Panel boxes, Fire extinguishers and cabinets, and fire hose
           cabinets/enclosures

h.      Vinyl (Resilient) Tile Floors: All resilient tile floors shall be dusted
        with a treated dust mop. All spillage will be removed, including damp
        mop cleaning when required. (Spray buff floor, using a commercial floor
        polishing machine, synthetic fiber pad and an approved acrylic polymer
        finish as required to maintain gloss).

i.      Carpets: All carpets shall be thoroughly vacuumed. Special attention
        will be paid to all spills, spots and adherents for removal. Spot clean
        carpeting as required.

j.      Glass Partitions: All glass partitions will be washed to remove
        fingermarks and smudges.


3.      Other Cleanable Areas


Main Entrance Lobby - Elevators - Corridors - Snack Bars Stairways, Landings,
Loading Platforms, and Receiving Rooms


The areas listed above are to receive complete daily cleaning as prescribed in
paragraphs A I and 2 above and specialty cleaning according to the
specifications listed below.

                                      D-3
<PAGE>

a.      Main Entrance Lobby: All hard surface floors shall be thoroughly cleaned
        and non-slip floor finish applied as necessary. (Spray buff floor, using
        a commercial floor polishing machine, synthetic fiber pad and an
        approved acrylic polymer finish as required to maintain gloss). All
        entrance door glass shall be cleaned. Area mats shall be removed and
        thoroughly cleaned and returned to their original location. Carpet areas
        shall be vacuumed and spot cleaned as necessary.

b.      Elevators: Interior walls and ceilings shall be dusted with a treated
        dust cloth and spot cleaned as required. All carpets shall be vacuumed
        and stains removed when possible. Telephone boxes shall be checked and
        cleaned of any trash/ashes, etc.

c.      Corridors/Snack Bars:


        (1)     Carpeted areas shall be vacuumed and all stains removed when
                possible. Resilient flooring shall be swept and damp mopped to
                remove spillage. (Spray buff floor, using a commercial floor
                polishing machine, synthetic fiber pad and an approved acrylic
                polymer finish as required to maintain gloss).


        (2)     All refuse, trash and garbage from snack bars and vending
                machine areas shall be collected and removed from the building.
                Cans used for collection of food remnants shall be periodically
                washed inside and out.

d.      Water Fountains: To insure a clean, health condition at the water
        fountains, the dispensing area shall be washed, cleaned and polished.

e.      Stairways: Stair landings and steps shall be swept or vacuumed. Hand
        railing, ledges, grilles, fire apparatus and doors shall be dusted.
        Spills shall be wiped up daily. Spray buff resilient flooring as
        required to maintain gloss.

f.      Outside Entrances: Landings and steps shall be swept. Both sides of
        entrance glass shall be cleaned. Kick plates and push bars shall be
        cleaned and polished.

g.      Loading Platforms/Receiving Rooms: Loading dock areas, platforms and
        receiving rooms shall be swept daily and damp mopped as required.


PART B - WEEKLY SERVICES


1.      Toilet Rooms

        Damp clean and dry polish tile walls.

2.      Room Cleaning


        a.      Vertical Surfaces:

                (1)     Wood wall paneling in Executive Offices shall be dusted
                        using a treated dust cloth.



                                      D-4
<PAGE>


          (2)   Dust vertical surfaces of cabinets, files, etc.


          (3)   All woodwork, doors, walls (including stairwells (,shall be
                spot cleaned to remove smudges/spills etc.


        b.      Other


                (1)     Air conditioning return air grills shall be cleaned
                        (vacuumed if necessary).


                (2)     Vacuum all upholstered furniture and clean any leather
                        furniture with a treated cloth.


3.      Other Cleanable Areas


        Stairways and Landings: All stairways and landings shall be damp mopped
weekly. Dust light fixtures and exposed pipes in stairwells.


PART C - MONTHLY SERVICES


1.      Toilet Rooms

        Dust all high areas and vacuum exhaust grills.

2.      Rooms Cleaning


        a.      Vertical surfaces and under surfaces (knee wells, chair rungs,
                table legs, etc.,) shall be thoroughly dusted and all glass in
                doors, partitions, pictures, and bookcases shall be damp-wiped.
                Dust walls and horizontal surfaces over six feet high.


        b.      Venetian Blinds: Venetian blinds will be dusted in place with a
                treated dust cloth or venetian blind tool.


3.      Other Cleanable Areas


        Elevators: Carpet shall be lifted where appropriate, and flooring swept
and damp mopped.



                                      D-5

<PAGE>



                              EXHIBIT "E" TO LEASE


                             DATED August 12, 1993


                                    BETWEEN


                        HYATT PLAZA LIMITED PARTNERSHIP
                                   (Landlord)


                                      and


                      AMERICAN MANAGEMENT SYSTEMS, INC.
                                    (Tenant)


                              HVAC SPECIFICATIONS


      The Building HVAC system consists of floor-by-floor variable air volume
air handling units.  The typical floor unit provides nominal cooling capacity
of approximately 78 tons.  The air handling units are served by two cooling
towers with a total nominal tonnage of 1,120.  There is a spare capacity in
the condenser water system of approximately 300 tons to more than handle any
supplemental cooling that may be required within the building for special
areas, such as computer rooms or training labs.


      The air is distributed throughout each floor through VAV boxes with
maximum perimeter zones of 1,600 CFM and maximum interior zones of 1,800 CFM.
Heat is provided through electric reheat coils in the VAV boxes, which is
supplemented in certain areas by baseboard heat as well.


      The Building is controlled by the EMS which is designed to turn
equipment off and on in the most energy and cost efficient manner.  The system
also provides for after hours usage by each tenant through an access code that
can be implemented via a touch tone phone.


      Subject to any limitations imposed by governmental authorities having
jurisdiction thereover, the HVAC equipment shall maintain an indoor temperature
of 76 degrees FDB in the summer, so long as the Washington National Airport
outdoor temperature is below 93 degrees FDB and 76 degrees FWB, and of 70
degrees FDB in the winter, so long as the Washington National Airport outdoor
temperature is above 14 degrees FDB.


      The Building system also contains toilet exhaust, general exhaust, smoke
exhaust and elevator and stairwell pressurization systems to meet local fire
codes.


                                      E-1

<PAGE>



                              EXHIBIT "F" TO LEASE


                             DATED August 12, 1993


                                    BETWEEN


                        HYATT PLAZA LIMITED PARTNERSHIP
                                   (Landlord)


                                      and


                      AMERICAN MANAGEMENT SYSTEMS, INC.
                                    (Tenant)


                            BARRIER REMOVAL PROGRAM


<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------
                                                              PLANNED
  ELEMENT               BARRIER              LOCATION       CORRECTIONS
- -------------------------------------------------------------------------------
<S>         <C>                           <C>           <C>
    2.0      Insufficient amount and/or    Parking Lot  At next planned lot
             style of accessible parking                resurfacing/restriping
             spaces
- -------------------------------------------------------------------------------

    3.0      Curb ramp needs detectable    East         Footnote 1
             warnings                      Entrance
- -------------------------------------------------------------------------------

    4.0      Inaccessible entrance needs   West         Footnote 1
             directional signage           Entrance
- -------------------------------------------------------------------------------

    8.0      Floor buttons need braille    All Cabs     Footnote 1
             designations
- -------------------------------------------------------------------------------

    10.0     Door closers do not meet ADA  Rest Rooms,  In process during
             requirements for maximum      Corridor     1993
             opening force                 Doors
- -------------------------------------------------------------------------------

    12.3     Urinals mounted above         All Rest     Footnote 1
             maximum height (24" vs. 17")  Rooms
- -------------------------------------------------------------------------------

    15.0     No AV devices in rest rooms   All Rest     Footnote 1
                                           Rooms
- -------------------------------------------------------------------------------
</TABLE>


                                      F-1

<PAGE>




<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------
                                                              PLANNED
  ELEMENT               BARRIER              LOCATION       CORRECTIONS
- ----------------------------------------------------------------------------
<S>         <C>                           <C>           <C>
    17.0     Public telephone needs        First Floor  At next scheduled
             volume controls and signage   Corridor     replacement of
             per ADA standard                           wall finishes in
                                                        this area
            ----------------------------------------------------------------
             Public telephone mounted      First Floor  At next scheduled
             above maximum allowable       Corridor     replacement of
             height                                     wall finishes in
                                                        this area
- ----------------------------------------------------------------------------
</TABLE>






Footnote 1: All items with this footnote are being remedied gradually, taking
            into consideration priority of barrier as well operational and
            budget considerations.  It is the intent to have all these
            barriers eliminated by not later than 1995.



                                      F-2

<PAGE>


                              EXHIBIT "G" TO LEASE


                             DATED August 12, 1993


                                    BETWEEN


                        HYATT PLAZA LIMITED PARTNERSHIP
                                   (Landlord)


                                      and


                      AMERICAN MANAGEMENT SYSTEMS, INC.
                                    (Tenant)



                             RULES AND REGULATIONS



      This Exhibit "G" is attached to and made a part of that Office Lease
Agreement dated August 12, 1993 (the "Lease"), between HYATT PLAZA LIMITED
PARTNERSHIP ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC. ("Tenant").
Unless the context otherwise requires the terms used in this Exhibit that are
defined in the Lease shall have the same meanings as provided in the Lease.


     The following rules and regulations have been formulated for the safety
and well-being of all tenants of the Building and to ensure compliance with
governmental and other requirements.  Any continuing violation of these rules
and regulations by Tenant shall constitute a Default by Tenant under the Lease.


      Landlord may, upon request of any Tenant, waive compliance by such
Tenant with any of the following rules and regulations, provided (i) no waiver
shall be effective unless signed by Landlord; (ii) any such waiver shall not
relieve such Tenant from the obligation to comply with such rule or regulation
in the future unless otherwise agreed to by Landlord; (iii) no waiver granted
to any Tenant shall relieve any other tenant from the obligation of complying
with these rules and regulations, unless such other tenant has received a
similar written waiver from Landlord; and (iv) any such waiver by Landlord
shall not relieve Tenant from any liability to Landlord for any loss or damage
occasioned as a result of Tenant's failure to comply with any rule or
regulation.


      1.  Sidewalks, plaza areas, entrances, courts, elevators, stairways,
corridors and all other public areas of the Building shall not be obstructed or
encumbered by any tenant or used for any purpose other than ingress and egress
to and from the premises of such tenant.


      2.  No awnings or other projections shall be attached to the outside wall
or windows of the Building. No curtains, blinds, shades, or screens (other than
those furnished as part of the



                                      G-1
<PAGE>

Leasehold Improvements or approved by Landlord as part of an Alteration) shall
be attached to or hung in, or used in connection with, any window or door of the
premises of any tenant.


      3.  Except as otherwise permitted by Sections 24.01, 24.02 and 24.04 of
the Lease, no showcases or other articles shall be put in front of or affixed to
any part of the exterior of the Building, nor placed in the corridor, or other
public areas of the Building.


      4.  Plumbing fixtures and appliances shall be used only for the purposes
for which they were constructed, and no sweepings, rubbish, rags, or other
substances (including, without limitation, coffee grounds) shall be thrown
therein. The cost of repairing any stoppage or damage resulting from misuse of
such fixtures by a tenant or such tenant's servants, employees, agents,
visitors, or licensees, shall be paid by such tenant.


      5.  No tenant shall bring or keep, or permit to be brought or kept, any
inflammable, combustible, or explosive fluid, materials, chemical, or substance
in or about its premises; however, substances used in modern offices may be
brought into and stored (in reasonable quantities) in the Premises.


      6.  Except for paintings or other typical wall hangings, no tenant shall
mark, paint, drill into, or in any way deface, any part of the Building or its
premises. No boring, cutting, or stringing of wires shall be permitted unless
approved as part of an Approved Plan.


      7.  No cooking shall be done or permitted in the Building by any tenant,
except for that which is consistent with an employee kitchen within the
premises. No tenant shall cause or permit any unusual or objectionable odors to
emanate from its premises.


      8.  Neither the whole nor any part of the premises of any tenant shall be
used for manufacturing, for the storage of. merchandise, or for the sale or
exchange of merchandise, goods, or property of any kind.


      9.  Tenants shall not construct, maintain, use, or operate within their
respective premises any electrical device, wiring, or apparatus in connection
with a loud-speaker system or other sound system, except as reasonably required
as part of a communication system approved prior to the installation thereof by
Landlord. No such loud-speaker system shall be constructed, maintained, used or
operated outside of the premises.


      10. No tenant shall make, or permit to be made, any unseemly or disturbing
noises or disturb or interfere with other tenants or occupants of the Building
or neighboring buildings whether by the use of any musical instrument, radio,
television, or other audio device, whistling, singing, or in any other way.
Nothing shall be thrown out of any doors, windows, or any passageways.


      11. Except as permitted by the Lease, no additional locks or bolts of any
kind shall be placed upon any of the doors or windows by and tenant, nor shall
any changes be made in any existing locks or the locking mechanisms therein,
without landlord's approval. The doors leading to the corridors or main halls
shall be kept closed during business hours except as they may


                                      G-2
<PAGE>

be used for ingress or egress. Each tenant shall, upon the termination of its
tenancy, restore to Landlord all keys of offices and storage and toilet rooms
either furnished to, or otherwise procured by, such tenant. In the event of the
loss of any keys so furnished, such tenant shall pay to Landlord the replacement
cost thereof.


      12. The normal hours of operation of the Building shall be 7:00 a.m. to 6
p.m. Monday through Friday, and 8 a.m. to 1 p.m. on Saturdays, customary legal
holidays excluded.


      13. No tenant shall use or occupy or permit any portion of its premises to
be used or occupied as an employment bureau or for the storage, manufacture, or
sale of liquor, narcotics, or drugs. Tenants may, however, have small quantities
of liquor or beer used for entertaining purposes. No tenant shall engage or pay
any employees in the Building, except those actually working for such tenant in
the Building, nor advertise for laborers giving an address at the Building.


      14. Landlord reserves the right to exclude from the Building at all times
any person who is not known or does not properly identify himself to the
Building management or watchman on duty, Landlord may at its option, require all
persons admitted to or leaving the Building between the hours of 6 p.m. and 7:00
a.m., Monday through Friday, and at any hour on Saturdays, Sundays, and legal
holidays, to register. Each Tenant shall be responsible for all persons for whom
it authorizes entry into the Building, and shall be liable to Landlord for all
acts or omissions of such persons.


      15. Each tenant, before closing and leaving its premises at any time,
shall lock all entrance doors and turn off all lights and electrical appliances.


      16. No premises shall be used, or permitted to be used, for lodging or
sleeping or for any immoral or illegal purpose.


      17. Landlord's employees shall not perform, and shall not be requested by
any tenant to perform, any work outside of their regular duties, unless under
specific instructions from the office of Landlord. The requirements of tenants
will be attended to only upon application to Landlord, and any such special
requirements shall be billed to tenants (and paid when the next installment of
rent is due) in accordance with the schedule of charges maintained by Landlord
from time to time or at such charge as is agreed upon in advance by Landlord and
such tenant.


      18. Canvassing, soliciting, and peddling in the Building are prohibited,
and each tenant shall cooperate in seeking their prevention.


      19. Except for trained animals assisting persons with disabilities, no
animals of any kind shall be brought into or kept about the Building by any
tenant.


      20. No vending machines for commercial or public use shall be permitted to
be placed or installed in any part of the Building by any Tenant. Tenant may
have vending machines in kitchen or other non-public areas of the Premises
and/or employee kitchen areas so long as (i) such machines are not available for
use by the general public; (ii) Landlord has approved such


                                      G-3
<PAGE>

machines and (iii) the machines are not visible to the exterior of the Premises
or the Building. Landlord reserves the right to place or install vending
machines in any of the public areas of the Building.


      21. No plumbing or electrical fixtures shall be installed by any Tenant
without the written consent of Landlord.


      22. Bicycles, motorcycles, or any other type of vehicle shall not be
brought into the lobby or elevators of the Building or into the premises of any
tenant.


      23. Landlord has the right to evacuate the Building in event of emergency
or catastrophe.


      24. Landlord reserves the right to rescind any of these Rules and
Regulations and make such other and further rules and regulations as in the
judgment of Landlord shall from time to time be needed for the safety,
protection, care, and cleanliness of the Building, the operation thereof, the
preservation of good order therein, and the protection and comfort of its
tenants, their agents, employees, and invitees, which Rules and Regulation when
made and notice thereof given to a Tenant shall be binding upon him in like
manner as if originally herein prescribed.



                                      G-4
<PAGE>




                              EXHIBIT "H" TO LEASE


                             DATED August 12, 1993


                                    BETWEEN


                        HYATT PLAZA LIMITED PARTNERSHIP
                                   (Landlord)


                                      and


                      AMERICAN MANAGEMENT SYSTEMS, INC.
                                    (Tenant)



                         SUBORDINATION, NON-DISTURBANCE
                            AND ATTORNMENT AGREEMENT



        THIS AGREEMENT is dated the _____ day of _____________, 19__, and is
made between THE AETNA CASUALTY AND SURETY COMPANY or one or more of its
affiliates or designees ("Mortgagee"), and _________________________________
________ ("Tenant").


                                   RECITALS:


        (a)     Tenant has entered into a certain lease ("Lease") dated
_________________ with _______________________________________ as lessor
("Landlord"), covering certain premises known as ____________________________
_____________ and located in ________________________________________________
___ (the "Demised Premises"); and


        (b)     Mortgagee has agreed to make a mortgage loan in the amount of
___________________________________ Dollars ($________) (the "Mortgage") to the
Landlord, secured by the Demised Premises, and the parties desire to set forth
their agreement herein.


        NOW, THEREFORE, in consideration of the Demised Premises and of the sum
of ONE DOLLAR ($1.00) by each party in hand paid to the other, the receipt of
which is hereby acknowledged, the parties hereby agree as follows:


        1.      Said Lease is and shall be subject and subordinate to the
Mortgage insofar as it affects the real property of which the Demised Premises
for a part, and to all renewals, modifications, consolidations, replacements and
extensions thereof, to the full extent of amounts secured thereby and interest
thereon.


        2.      Tenant agrees that it will attorn to and recognize any purchaser
at a foreclosure sale under the Mortgage, any transferee who acquires the
Demised Premises by deed in lieu of foreclosure, and the successors and assigns
of such purchaser(s), as its landlord for the unexpired



                                      H-1
<PAGE>

balance (and any extensions, if exercised) of the term of said Lease upon the
same terms and conditions set forth in said Lease.


        3.      If it becomes necessary to foreclose the Mortgage, Mortgagee
will not terminate said lease nor join Tenant in summary or foreclosure
proceedings so long as Tenant is not in default under any of the terms,
covenants, or conditions of said Lease.


        4.      If Mortgagee succeeds to the interest of Landlord under the
Lease, Mortgagee shall not be:


                a.     liable for any act or omission of any prior landlord
(including Landlord); or


                b.     liable for the return of any security deposit; or


                c.     subject to any offsets or defenses which Tenant might
have against any prior landlord (including Landlord); or


                d.      bound by any rent or additional rent which Tenant might
have paid for more than the current month to any prior landlord (including
Landlord); or


                e.      bound by any amendment or modification of the Lease made
without its consent.


        5.      This Agreement shall be binding upon and shall inure to the
benefit of the parties hereto and their successors and assigns.


        6.      Tenant agrees to give Mortgagee, by registered mail, a copy of
any notice of default served upon the Landlord, provided that prior to such
notice Tenant has been notified in writing (by way of Notice of Assignment of
Rents and Leases, or otherwise), of the address of such Mortgagee. Tenant
further agrees that if Landlord shall have failed to cure such default within
the time provided for in this Lease, then the Mortgagee shall have an additional
sixty (60) days within which to cure such default or if such default cannot be
cured within that time, then such additional time as may be necessary to cure
such default shall be granted if within such sixty (60) days Mortgagee has
commenced and is diligently pursuing the remedies necessary to cure such default
(including, but not limited to, commencement of foreclosure proceedings, if
necessary to effect such cure), in which event the Lease shall not be terminated
while such remedies are being so diligently pursued.


                                      H-2


<PAGE>



        IN WITNESS WHEREOF, the parties hereto have executed these presents as
of the day and year first above written.





                                    Mortgagee:
- ---------------------------------              -----------------------------
Date
                                    By:
                                        ------------------------------------
                                        Its:


                                    Address:   c/o AEtna Realty Investors, Inc.
                                               242 Trumbull
                                               Hartford, CT  06156





                                    Tenant:
- ---------------------------------              -----------------------------
Date
                                    By:
                                        ------------------------------------
                                        Its:



                                      H-3

<PAGE>
                   FIRST AMENDMENT TO OFFICE LEASE AGREEMENT

         THIS FIRST AMENDMENT TO OFFICE LEASE AGREEMENT (the "First Amendment")
is made and entered into this day ___ of _________, 1994 (the "Effective
Date"), by and between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia limited
partnership ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware
corporation ("Tenant"), with reference to the following:

                                   RECITALS:

         A.      Pursuant to an Office Lease Agreement dated August 12, 1993,
by and between Landlord and Tenant (the "Lease"), Landlord has leased to Tenant
certain premises located at 12701 Fair Lakes Circle, Fairfax, Virginia, as more
particularly described therein.  All capitalized terms used herein, unless
specifically defined, shall have the same meaning and definition as used in the
Lease.

         B.      Landlord and Tenant have agreed to amend the certain terms and
provisions of the Lease as hereinafter set forth.

                 NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged, Landlord and Tenant
agree as follows:

                 1. Under Tenant's Right of First Refusal option, Landlord and
Tenant have agreed to expand the Premises to include an additional 7,926 square
feet of Rentable Area located on the ninth (9th) floor of the Building (the
"Additional Space"), as more particularly shown on Exhibit "A" attached hereto
and made a part hereof by this reference.  Base Rent for the Additional Space
("Additional Space Base Rent") shall be at the rate of $16.50 per square foot
of Rentable Area, or the sum of $130,779.00 per year ($10,898.25 per month),
adjusted as hereinafter set forth.  Tenant shall lease the Additional Space in
its "as is" and "where as" condition, and Landlord shall have no obligation to
make any improvements as a condition of Tenant's acceptance thereof.  Tenant's
lease of the Additional Space shall commence on May 1, 1995 (the "Additional
Space Commencement Date") and shall terminate on April 30, 2000 (the
"Additional Space Expiration
<PAGE>
Date").  Provided, however, that Tenant shall have the right to commence
renovation of the Additional Space prior to the Additional Space Commencement
Date with Landlord's prior written approval.  Any entry upon the Additional
Space prior to the Additional Space Commencement Date shall be subject to all
of the terms and conditions of the Lease, as amended; however, Tenant's
obligations to pay Additional Space Rent hereunder shall commence on the
Additional Space Commencement Date.  Tenant's renovation of the Additional
Space shall be at Tenant's sole expense, and in accordance with the terms and
provisions of Exhibit "B" to the Lease.  On or before the Additional Space
Expiration Date, Tenant  shall surrender possession of the Premises to Landlord
in accordance with the terms of the Lease.

         2.  Commencing on January 1, 1996 and thereafter throughout the
Additional SpaceTerm (as hereinafter defined) Tenant shall pay on a monthly
basis, without demand, as Additional Rent for the Additional Space, Tenant's
Proportionate Share of the amount by which Operating Expenses exceed the Base
Operating Expenses.  The Base Year with respect to the Additional Space shall
be 1995.

         3.      (a) As used in the following paragraphs, the following terms
shall be deemed to refer to, and shall have the following meanings:

                          (1)     Consumer Price Index or CPI: The Consumer
Price Index for All Urban Consumers (CPI-U) for Washington,D.C.-Md.-Va.
All Items(1982-84=100),published by the Bureau of Labor Statistics, United
States Department of Labor.

                          (2)     Base CPI: The most recently published
Consumer Price Index as of the last day of the month immediately preceding the
Additional Space Commencement Date.

                          (3)     CPI Adjustment Factor: Thirty percent (30%).

                 (b)      During the Additional Space Term, the Additional
Space Base Rent shall be adjusted, pursuant to the terms of this Paragraph 2,
on the first day of January of each calendar year after the Additional Space
Commencement Date and on the first day of January annually thereafter during
the term of this First Amendment.  The dates described in this Paragraph 2 for
computing the adjustment of Additional Space Base Rent are hereinafter
sometimes referred to
<PAGE>
collectively as "Rental Adjustment Dates" and singularly as a "Rental
Adjustment Date".  All adjustments to Additional Space Base Rent required by
this Paragraph 2 shall be made as follows:

                          (1)The Base CPI shall be subtracted from the CPI
for the month immediately preceding a Rental Adjustment Date to determine the
changes in the CPI for such period.

                          (2)The number computed in (1) above shall be
divided by the Base CPI to yield a percentage of increase in the CPI.

                          (3)The percentage of increase computed in (2) above
shall be multiplied by the CPI Adjustment Factor.

                          (4)The Additional Space Base Rent (which amount
shall remain constant for purposes of this calculation) shall be multiplied by
the percentage computed in (3) above.

                          (5)The number computed in (4) above shall be
added to the Additional Space Base Rent set forth in (4) immediately above and
the resulting sum will be adjusted rent (hereinafter the "Additional Space
Adjusted Rent") to be paid by the Tenant to Landlord, in advance, without
demand, in equal monthly installments, on the first day of each calendar month
until the next Rental Adjustment Date.

                 (c)      In no event shall any adjustment made pursuant to
this Paragraph 2 ever result in an increase in the Adjusted Rent by more than
three percent (3%) of the Adjusted Rent in effect immediately prior to the
applicable Rental Adjustment Date, nor shall any adjustment made pursuant to
this Paragraph 2 ever result in a decrease in the Additional Space Adjusted
Rent below  the Additional Space Rent payable and in effect for the preceding
calendar year.  In the event of an adjustment which would otherwise cause a
decrease in the Additional Space Adjusted Rent, the Rent payable hereunder in
effect for the preceding year shall continue in effect until the next Rental
Adjustment Date.  Adjustments to Rent shall be effective on the first day of
January each year.

                 (d)      If (i) a significant change is made in the number or
nature (or both) of items used in determining the CPI, or (ii) the CPI shall be
discontinued for any reason, the Bureau of Labor Statistics shall be requested
to furnish a new index comparable to the CPI, together with
<PAGE>
information which will make possible the conversion to the new index in
computing the adjustment to Base Rent hereunder.  If for any reason the Bureau
of Labor Statistics does not furnish such an index and such information,
Landlord and Tenant shall instead accept and use such other index or comparable
statistics on the cost of living in the Washington, D.C. -Md. -Va.
metropolitan area, that is computed and published by an agency of the United
States or a responsible financial periodical of recognized authority.

         (e) Landlord shall provide Tenant with written notice of each
adjustment pursuant to this Paragraph 2, which notice shall provide the basis
upon which such adjustment has been calculated; provided, however, that if for
any reason Landlord does not notify Tenant of the amount of such adjustment
until after any Rental Adjustment Date, Tenant shall continue to pay the
Additional Space Base Rent or Adjusted Rent, as the case may be, payable prior
to the Rental Adjustment Date, and Tenant, within five (5) days following
Landlord's delivery of written notice of such adjustment, shall pay to Landlord
in a lump sum the amount of any increase in the Additional Space Base Rent
resulting from such adjustment for all months in the existing calendar year
prior to and including the month in which such notice of adjustment is received
and during the remainder of such year Tenant shall pay to Landlord the
Additional Space Adjusted Rent as set forth in such notice.

         4.      Tenant shall have the right to renew and extend the Additional
Space Term (the "Additional Space Term") with respect to the Additional Space
for one (1) Renewal Term (herein so called) upon and subject to the following
terms and conditions:

                 (a)Tenant may extend the Additional Space Term for one (1)
Renewal Term of four (4) years (such Renewal Term commencing on May 1, 2000 and
expiring concurrent with the Lease Term on February 29, 2004) by Tenant's
giving written notice thereof to Landlord no later than twelve (12) months
prior to the expiration of the original Additional Space Term.  If Tenant does
not exercise its rights to a Renewal Term in a timely manner, Tenant's failure
shall conclusively be deemed a waiver of its rights to a Renewal Term.
<PAGE>
                 (b)      The exercise by Tenant of its rights to a Renewal
Term must be made, if at all, by written notice executed by Tenant and
delivered to Landlord on or before the date set forth above.  Once Tenant shall
exercise its rights to a Renewal Tenn, Tenant may not thereafter revoke such
exercise.  Tenant  shall not have the right to exercise a Renewal Tenn if
Tenant is in Default under the Lease, as amended, either at the time Tenant
gives notice of its election or immediately prior to the commencement of the
Renewal Term.

                 (c)      Tenant shall take the Additional Space "as is" for
the Renewal Term and Landlord shall have no obligation to make any improvements
or alterations to the Additional Space.

                 (d)      Base Rent per square foot of Rentable Area of the
Additional Space for the first year of the Renewal Term shall be the current
Base Rent, as adjusted, in effect on May 1, 2000.  In no event shall the
Additional Space Base Rent for the first year of the Additional Space Renewal
Tenn be less than the Additional Space Base Rent in effect immediately prior to
the expiration of the original Additional Space Term.

                 (e)      Subject to subparagraph (e) above, the leasing of the
Additional Space for the Renewal Term shall be upon the same terms and
conditions as are applicable for the original Additional Space Term, and shall
be upon and subject to all of the provisions of the Lease, including, without
limitations the obligation of Tenant to pay Tenant's Additional Rent under the
Lease.

         5.      From and after the Additional Space Commencement Date until
the Additional Space Expiration Date, the following terms used in the Lease
shall have the following ascribed meanings:

                 (a)  Premises: Refers to the Rentable Area demised to Tenant
by the Lease (set forth therein) and to the Additional Space demised to Tenant
by this First Amendment, as more fully described and shown on the floor plan(s)
attached as Exhibit "A" hereto.

                 (b)  Additional space:  7,926 square feet of Rentable Area
located on the ninth (9th) floor of the Building, subject to adjustment
pursuant to Paragraph 2 of this Amendment.
<PAGE>
                 (c)  Additional Space Base Rent: $130,779.00 per year
($10,898.25 per month), based on $16.50 per square foot of Rentable Area of the
Premises, as adjusted.

                 (d)  Additional Space Base Year. 1995.

                 (e)  Tenant's Proportionate Share as to Additional Space:
3.14% subject to adjustment pursuant to Paragraph 2 of this First Amendment.

         6.      Except as expressly modified by this First Amendment, the
Lease remains unchanged and in full force and effect.

                        {Signatures appear on next page}

IN WITNESS WHEREOF, Landlord and Tenant have executed this First Amendment as
of the day and year first above written.

                                   LANDLORD:
                                   ---------

                                   HYATT PLAZA LIMITED PARTNERSHIP,
                                   a Virginia limited partnership


                                   By: Fair Lakes Hyatt Limited Partnership,
                                   a Virginia general partnership, its
                                   general partner


                                   By: Fair Lakes of Virginia, Inc.,
                                   a Virginia corporation



                                   By:
                                      --------------------------------
                                      Name:
                                           ---------------------------
                                      Its:
                                          ----------------------------


                                   TENANT:
                                   -------

                                   AMERICAN MANAGEMENT
                                   SYSTEMS, INC., a Delaware corporation


                                   By:
                                      --------------------------------
                                      Name:
                                           ---------------------------
                                      Its:
                                          ----------------------------
<PAGE>
[THE FOLLOWING PAGE INCLUDES AS EXHIBIT A A FLOOR PLAN OF THE ADDITIONAL SPACE]
<PAGE>
                   SECOND AMENDMENT TO OFFICE LEASE AGREEMENT


         THIS SECOND AMENDMENT TO OFFICE LEASE AGREEMENT (the "Second
Amendment") is made and entered into this 1st day of November, 1994 (the
"Effective Date"), by and between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia
limited partnership ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a
Delaware corporation ("Tenant"), with reference to the following:

                                   RECITALS:

         A.      Pursuant to an Office Lease Agreement dated August 12, 1993,
by and between Landlord and Tenant, as amended by that certain First Amendment
to Office Lease Agreement dated August 31, 1994 (collectively, the "Lease"),
Landlord has leased to Tenant certain premises located at 12701 Fair Lakes
Circle, Fairfax, Virginia, as more particularly described therein.  All
capitalized terms used herein, unless specifically defined, shall have the same
meaning and definition as used in the Lease.

         B.      Landlord and Tenant have agreed to amend the certain terms and
provisions of the Lease as hereinafter set forth.

                 NOW, THEREFORE, for good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged, Landlord and Tenant
agree as follows:

         1.      Under Tenant's Right of First Refusal option, Landlord and
Tenant have agreed to expand the Premises to include an additional 5,175 square
feet of Rentable Area located on the tenth (10th) floor of the Building (the
"Additional Space"), as more particularly shown on Exhibit "A" attached hereto
and made a part hereof by this reference.  Base Rent for the Additional Space
("Additional Space Base Rent") shall be at the rate of $16.50 per square foot
of Rentable Area, or the sum of $85,387.50 per year ($7,115.63 per month),
adjusted as hereinafter set forth.  Tenant shall lease the Additional Space in
its "as is" and "where as" condition, and Landlord shall have no obligation to
make any improvements as a condition of Tenant's acceptance thereof.  Tenant's
lease of the Additional Space shall commence on April 1, 1995 (the "Additional
Space





<PAGE>
Commencement Date") and shall terminate on March 30, 2000 (the "Additional
Space Expiration Date").  Provided, however, that Tenant shall have the right
to commence renovation of the Additional Space prior to the Additional Space
Commencement Date with Landlord's prior written approval.  Any entry upon the
Additional Space prior to the Additional Space Commencement Date shall be
subject to all of the terms and conditions of the Lease, as amended; however,
Tenant's obligations to pay Additional Space Rent hereunder shall commence on
the Additional Space Commencement Date.  Tenant's renovation of the Additional
Space shall be at Tenant's sole expense, and in accordance with the terms and
provisions of Exhibit "B" to the Lease.  On or before the Additional Space
Expiration Date, Tenant shall surrender possession of the Premises to Landlord
in accordance with the terms of the Lease.

         2.      Commencing on January 1, 1996 and thereafter throughout  the
Additional Space Term (as hereinafter defined) Tenant shall pay on a monthly
basis, without demand, as Additional Rent for the Additional Space, Tenant's
Proportionate Share of the amount by which Operating Expenses exceed the Base
Operating Expenses.  The Base Year with respect to the Additional Space shall
be 1995.

         3.      (a) As used in the following paragraphs, the following terms
shall be deemed to refer to, and shall have the following meanings:

                          (1)     Consumer Price Index or CPI: The Consumer
Price Index for All Urban Consumers(CPI-U)for Washington,D.C.-Md.-Va.  All
Items(1982-84=100), published by the Bureau of Labor Statistics, United States
Department of Labor.

                          (2)     Base CPI:  The most recently published
Consumer Price Index as of the last day of the month immediately preceding the
Additional Space Commencement Date.

                          (3)     CPI Adjustment Factor:  Thirty percent (30%).

                 (b)      During the Additional Space Term, the Additional
Space Base Rent shall be adjusted, pursuant to the terms of this Paragraph 2,
on the first day of January of each calendar year after the Additional Space
Commencement Date and on the first day of January annually





<PAGE>
thereafter during the term of this Second Amendment.  The dates described in
this Paragraph 2 for computing the adjustment of Additional Space Base Rent are
hereinafter sometimes referred to collectively as "Rental Adjustment Dates" and
singularly as a "Rental Adjustment Date".  All adjustments to Additional Space
Base Rent required by this Paragraph 2 shall be made as follows:

                          (1)     The Base CPI shall be subtracted from the CPI
for the month immediately preceding a Rental Adjustment Date to determine the
changes in the CPI for such period.

                          (2)     The number computed in (1) above shall be
divided by the Base CPI to yield a percentage of increase in the CPI.

                          (3)     The percentage of increase computed in (2)
above shall be multiplied by the CPI Adjustment Factor.

                          (4)     The Additional Space Base Rent (which amount
shall remain constant for purposes of this calculation) shall be multiplied by
the percentage computed in (3) above.

                          (5)     The number computed in (4) above shall be
added to the Additional Space Base Rent set forth in (4) immediately above and
the resulting sum will be the adjusted rent (hereinafter the "Additional Space
Adjusted Rent") to be paid by the Tenant to Landlord, in advance, without
demand, in equal monthly installments, on the first day of each calendar month
until the next Rental Adjustment Date.

                 (c)      In no event shall any adjustment made pursuant to
this Paragraph 2 ever result in an increase in the Adjusted Rent by more than
three percent (3%) of the Adjusted Rent in effect immediately prior to the
applicable Rental Adjustment Date, nor shall any adjustment made pursuant to
this Paragraph 2 ever result in a decrease in the Additional Space Adjusted
Rent below the Additional Space Rent payable and in effect for the preceding
calendar year.  In the event of an adjustment which would otherwise cause a
decrease in the Additional Space Adjusted Rent, the Rent payable hereunder in
effect for the preceding year shall continue in effect until the next





3
<PAGE>
Rental Adjustment Date.  Adjustments to Rent shall be effective on the first
day of January each year.

                 (d)      If (i) a significant change is made in the number or
nature (or both) of items used in determining the CPI, or (ii) the CPI shall be
discontinued for any reason, the Bureau of Labor Statistics shall be requested
to furnish a new index comparable to the CPI, together with information which
will make possible the conversion to the new index in computing the adjustment
to Base Rent hereunder.  If for any reason the Bureau of Labor Statistics does
not furnish such an index and such information, Landlord and Tenant shall
instead accept and use such other index or comparable statistics on the cost of
living in the Washington, D.C.-Md.-Va. metropolitan area, that is computed and
published by an agency of the United States or a responsible financial
periodical of recognized authority.

                 (e)      Landlord shall provide Tenant with written notice of
each adjustment pursuant to this Paragraph 2, which notice shall provide the
basis upon which such adjustment has been calculated; provided, however, that
if for any reason Landlord does not notify Tenant of the amount of such
adjustment until after any Rental Adjustment Date, Tenant shall continue to pay
the Additional Space Base Rent or Adjusted Rent, as the case may be, payable
prior to the Rental Adjustment Date, and Tenant, within five (5) days following
Landlord's delivery of written notice of such adjustment, shall pay to Landlord
in a lump sum the amount of any increase in the Additional Space Base Rent
resulting from such adjustment for all months in the existing calendar year
prior to and including the month in which such notice of adjustment is received
and during the remainder of such year Tenant shall pay to Landlord the
Additional Space Adjusted Rent as set forth in such notice.

         4.      Tenant shall have the right to renew and extend the Additional
Space Term (the "Additional Space Term") with respect to the Additional Space
for one (1) Renewal Term (herein so called) upon and subject to the following
terms and conditions:

                 (a)      Tenant may extend the Additional Space Term for one
(1) Renewal Term of four (4) years (such Renewal Term commencing on April 1,
2000 and expiring concurrent with the





<PAGE>
Lease Term on February 29, 2004) by Tenant's giving written notice thereof to
Landlord no later than twelve (12) months prior to the expiration of the
original Additional Space Term.  If Tenant does not exercise its rights to a
Renewal Term in a timely manner, Tenant's failure shall conclusively be deemed
a waiver of its rights to a Renewal Term.

                 (b)      The exercise by Tenant of its rights to a Renewal
Term must be made, if at all, by written notice executed by Tenant and
delivered to Landlord on or before the date set forth above.  Once Tenant shall
exercise its rights to a Renewal Term, Tenant may not thereafter revoke such
exercise.  Tenant shall not have the right to exercise a Renewal Term if Tenant
is in Default under the Lease, as amended, either at the time Tenant gives
notice of its election or immediately prior to the  commencement of the Renewal
Term.

                 (c)      Tenant shall take the Additional Space "as is" for
the Renewal Term and Landlord shall have no obligation to make any improvements
or alterations to the Additional Space.

                 (d)      Base Rent per square foot of Rentable Area of the
Additional Space for the first year of the Renewal Term shall be the current
Base Rent, as adjusted, in effect on April 1, 2000.  In no event shall the
Additional Space Base Rent for the first year of the Additional Space Renewal
Term be less than the Additional Space Base Rent in effect immediately prior to
the expiration of the original Additional Space Term.

                 (e)      Subject to subparagraph (e) above, the leasing of the
Additional Space for the Renewal Term shall be upon the same terms and
conditions as are applicable for the original Additional Space Term, and shall
be upon and subject to all of the provisions of the Lease, including, without
limitation, the obligation of Tenant to pay Tenant's Additional Rent under the
Lease.

         5.      From and after the Additional Space Commencement Date until
the Additional Space Expiration Date, the following terms used in the Lease
shall have the following ascribed meanings:





5
<PAGE>
                 (a)      Premises: Refers to the Rentable Area demised to
Tenant by the Lease (set forth therein) and to the Additional Space demised to
Tenant by the First Amendment and the Additional Space demised to Tenant by
this Second Amendment, as more fully described and shown on the floor plan(s)
attached as Exhibit "A" hereto.

                 (b)      Additional Space: 5,175 square, feet of Rentable Area
located on the tenth (10th) floor of the Building, subject to adjustment
pursuant to Paragraph 2 of this Amendment.

                 (c)      Additional Space Base Rent: $85,387.50 per year
($7,115.65 per month), based on $16.50 per square foot of Rentable Area of the
Additional Space as adjusted.

                 (d)      Additional Space Base Year. 1995.

                 (e)      Tenant's Proportionate Share as to Additional Space:
2.05% subject to adjustment pursuant to Paragraph 2 of this Second Amendment.

         6.      Except as expressly modified by this Second Amendment, the
Lease remains unchanged and in full force and effect.





<PAGE>
IN WITNESS WHEREOF, Landlord and Tenant have executed this Second Amendment as
of the day and year first above written.


                           LANDLORD:
                           ---------

                           HYATT PLAZA LIMITED PARTNERSHIP,
                           a Virginia limited partnership

                           By:     Fair Lakes Hyatt Limited Partnership, a
                           Virginia general partnership, its general partner

                           By:     Fair Lakes of Virginia, Inc., a Virginia
                           corporation


                           By:          [SIG]
                             --------------------------------
                           Name:
                                -----------------------------
                           Its:
                               ------------------------------


                           TENANT:
                           -------

                           AMERICAN MANAGEMENT SYSTEMS, INC.,
                           a Delaware corporation

                           By:  /s/ Frank A. Nicolai
                             --------------------------------
                           Name:   Frank A. Nicolai
                                -----------------------------
                           Its:    Executive Vice President,
                               ------------------------------
                                   Secretary and Treasurer
                               ------------------------------




7
<PAGE>
                   THIRD AMENDMENT TO OFFICE LEASE AGREEMENT

THIS THIRD AMENDMENT TO OFFICE LEASE AGREEMENT (this "Third Amendment") is made
and entered into this 2nd day of October 1995 (the "Effective Date"), by and
between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia limited partnership
("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a Delaware corporation
("Tenant"), with reference to the following:


                                   RECITALS:


         A.      Pursuant to an Office Lease Agreement dated August 12, 1993,
by and between Landlord and Tenant, as amended by that certain (i) First
Amendment to Office Lease Agreement dated August 31, 1994 and (ii) Second
Amendment Office Lease Agreement dated November 1, 1994 (collectively, the
"Lease"), Landlord has leased to Tenant certain premises located at 12701 Fair
Lakes Circle, Fairfax, Virginia, as more particularly described therein.  All
capitalized terms used herein, unless specifically defined, shall have the same
meaning and definition as used in the Lease.

         B.      Landlord and Tenant have agreed to amend the certain terms and
provisions of the Lease as hereinafter set forth.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Landlord and Tenant agree as
follows:


1.       Under Tenant's Right of First Refusal option, Landlord and Tenant have
agreed to expand the Premises to include an additional 5,327 square feet of
Rentable Area located on the third (3rd) floor of the Building (the "Third
Amendment Space"), commonly known as Suite 320, as





<PAGE>
more particularly shown on Exhibit "A" attached hereto and made a part hereof
by this reference.  Base Rent for the Third Amendment Space ("Third Amendment
Space Base Rent") shall be at the rate of $17.00 per square foot of Rentable
Area, or the sum of $90,559.00 per year ($7,546.58 per month), adjusted as
hereinafter set forth.  Tenant shall lease the Third Amendment Space in its "as
is" and "where as" condition, and Landlord shall have no obligation to make any
improvements as a condition of Tenant's acceptance thereof.  Notwithstanding,
Landlord agrees to provide Tenant with a Renovation Allowance of up to $5.00
per rentable square foot in the Third Amendment Space.  Landlord shall
reimburse Tenant for approved improvements to the Third Amendment Space within
thirty (30) days after receipt of invoices from Tenant.  Tenant's lease of
Third Amendment Space shall commence January 1, 1996 (the "Third Amendment
Space Commencement Date") and shall terminate on December 31, 2000 (the "Third
Amendment Space Expiration Date") (the "Third Amendment Space Initial Term").
Provided, however, that Tenant shall have the right to commence renovation of
the Third Amendment Space prior to the Third Amendment Space Commencement Date
and after October 1, 1995 with Landlord's prior written approval.  Any entry
upon the Third Amendment Space prior to the Third Amendment Space Commencement
Date shall be subject to all of the terms and conditions of the Lease, as
amended; however, Tenant's obligations to pay Third Amendment Space Base Rent
and Third Amendment Space Additional  Rent (as hereinafter defined) shall
commence on the Third Amendment Space Commencement Date.  Tenant's renovation
of the Third Amendment Space shall be at Tenant's sole expense, and in
accordance with the terms and provisions of Exhibit "B" to the Lease.  On or
before the Third Amendment Space Expiration Date, Tenant shall surrender
possession of the Premises to Landlord in accordance with the terms of the
Lease.

2.       Commencing on January 1, 1997 and thereafter throughout the Third
Amendment Space Initial Term Tenant shall pay on a monthly basis, without
demand, as Additional Rent for the Third Amendment Space, 2.11% of the amount
by which Operating Expenses exceed the Adjusted Base Operating Expenses.
Adjusted Base Operating Expenses shall, for purposes of this Amendment, refer
to the Operating Expenses incurred during the 1996 calendar





                                       2
<PAGE>
year.  Such payments shall be made in accordance with Section 6.01 of the
Lease.

3.       (a)     As used in the following paragraphs, the following terms shall
be deemed to refer to, and shall have the following meanings:

                 (1)      Consumer Price Index or CPI: The Consumer Price Index
for All Urban Consumers (CPI-U) for Washington, D.C.-Md.-Va. All Items
(1982-84=100), published by the Bureau of Labor Statistics, United States
Department of Labor.

                 (2)      Base CPI: The most recently published Consumer Price
Index as of the last day of the month immediately preceding the Third Amendment
Space Commencement Date.

                 (3)      CPI Adjustment Factor: Thirty percent (30%).

         (b)     During the Third Amendment Space Initial Term, the Third
Amendment Space Base Rent shall be adjusted, pursuant to the terms of this
Paragraph 3, on the first day of January of each calendar year after the Third
Amendment Space Commencement Date and on the first day of January annually
thereafter during the term of this Third Amendment.  The dates described in
this Paragraph 3 for computing the adjustment of Third Amendment Space Base
Rent are hereinafter sometimes referred to collectively as "Rental Adjustment
Dates" and singularly as a "Rental Adjustment Date".  All adjustments to Third
Amendment Space Base Rent required by this Paragraph 3 shall be made as
follows:





                                       3
<PAGE>
                 (1)      The Base CPI shall be subtracted from the CPI for the
month immediately preceding a Rental Adjustment Date to determine the changes
in the CPI for such period.

                 (2)      The number computed in (1) above shall be divided by
the Base CPI to yield a percentage of increase in the CPI.

                 (3)      The percentage of increase computed in (2) above
shall be multiplied by the CPI Adjustment Factor.

                 (4)      The Third Amendment Space Base Rent (which amount
shall remain constant for purposes of this calculation) shall be multiplied by
the percentage computed in (3) above.

                 (5)      The number computed in (4) above shall be added to
the Third Amendment Space Base Rent set forth in (4) immediately above and the
resulting sum will be the adjusted rent (hereinafter the "Third Amendment Space
Adjusted Rent") to be paid by Tenant to Landlord, in advance, without demand,
in equal monthly installments, on the first day of each calendar month until
the next Rental Adjustment Date.

         (c)     In no event shall any adjustment made pursuant to this
Paragraph 3 ever result in an increase in the Third Amendment Space Adjusted
Rent by more than three percent (3%) of the Third Amendment Space Adjusted Rent
in effect immediately prior to the applicable Rental





                                       4
<PAGE>
Adjustment Date, nor shall any  adjustment made pursuant to this Paragraph 3
ever result in a decrease in the Third Amendment Space Adjusted Rent below the
Third Amendment Space Base Rent and Third Amendment Space Additional Rent
payable and in effect for the preceding calendar year.  In the event of an
adjustment which would otherwise cause a decrease in the Third Amendment Space
Adjusted Rent, the Rent payable hereunder in effect for the preceding year
shall continue in effect until the next Rental Adjustment Date.  Adjustments to
Rent shall be effective on the first day of January each year.

         (d)     If (i) a significant change is made in the number or nature
(or both) of items used in determining the CPI, or (ii) the CPI shall be
discontinued for any reason, the Bureau of Labor Statistics shall be requested
to furnish a new index comparable to the CPI, together with information which
will make possible the conversion to the new index in computing the adjustment
to Base Rent hereunder.  If for any reason the Bureau of Labor Statistics does
not furnish such an index and such information, Landlord and Tenant shall
instead accept and use such other index or comparable statistics on the cost of
living in the Washington, D.C. -Md. -Va. metropolitan area, that is computed
and published by an agency of the United States or a responsible financial
periodical of recognized authority.

         (e)     Landlord shall provide Tenant with written notice of each
adjustment pursuant to this Paragraph 2, which notice shall provide the basis
upon which such adjustment has been calculated; provided, however, that if for
any reason Landlord does not notify Tenant of the amount of such adjustment
until after any Rental Adjustment Date, Tenant shall continue





                                       5
<PAGE>
to pay the Third Amendment Space Base Rent or Adjusted Rent, as the case may
be, payable prior to the Rental Adjustment Date, and Tenant, within five (5)
days following Landlord's delivery of written notice of such adjustment, shall
pay to Landlord in a lump sum the amount of any increase in the Third Amendment
Space Base Rent resulting from such adjustment for all months in the existing
calendar year prior to and including the month in which such notice of
adjustment is received and during the remainder of such year Tenant shall pay
to Landlord the Third Amendment Space Adjusted Rent as set forth in such
notice.

4.       Tenant shall have the right to renew and extend the Third Amendment
Space Initial Term (the "Third Amendment Space Renewal Term") with respect to
the Third Amendment Space for one (1) Renewal Term (herein so called) upon and
subject to the following terms and conditions:

         (a)     Tenant may extend the Third Amendment Space Initial Term for
one (1) Renewal Term of five (5) years (such Renewal Term commencing on January
1, 2001 and expiring on December 31, 2005 by Tenant's giving written notice
thereof to Landlord no later, than twelve (12) months prior to the expiration
of the Third Amendment Space Initial Term.  If Tenant does not exercise its
rights to a Renewal Term in a timely manner, Tenant's failure shall
conclusively be deemed a waiver of its rights to a Renewal Term.

         (b)     The exercise by Tenant of its rights to a Renewal Term must be
made, if at all, by written notice executed by Tenant and delivered to Landlord
on or before the date set forth above.  Once Tenant shall exercise its rights
to a Renewal Term, Tenant may not thereafter





                                       6
<PAGE>
revoke such exercise.  Tenant shall not have the right to exercise a Renewal
Term if Tenant is in Default under the Lease, as amended, either at the time
Tenant gives notice of its election or  immediately prior to the commencement
of the Renewal Term.

         (c)     Tenant shall take the Third Amendment Space "as is" for the
Renewal Term and Landlord shall have no obligation to make any improvements or
alterations to the Third Amendment Space.

         (d)     Base Rent per square foot of Rentable Area of the Third
Amendment Space for the first year of the Renewal Term shall be the current
Third Amendment Space Base Rent, as adjusted, in effect on January 1, 2001.  In
no event shall the Third Amendment Space Base Rent for the first year of the
Third Amendment Space Renewal Term be less than the Third Amendment Space Base
Rent, as adjusted, in effect immediately prior to the expiration of the Third
Amendment Space Initial Term.

         (e)     Subject to subparagraph (d) above, the leasing of the Third
Amendment Space for the Renewal Term shall be upon the same terms and
conditions as are applicable for the Third Amendment Space Initial Term, and
shall be upon and subject to all of the provisions of the Lease, including,
without limitation, the obligation of Tenant to pay Tenant's Third Amendment
Space Additional Rent under the Lease.

5.       From and after the Third Amendment Space Commencement Date until the
Third





                                       7
<PAGE>
Amendment Space Expiration Date, the following terms used in the Lease shall
have the following ascribed meanings:

         (a)     Premises:  Refers to the Rentable Area demised to Tenant by
the Lease (set forth therein) and to the space demised to Tenant by the First
Amendment, Second Amendment and the Third Amendment Space demised to Tenant by
this Third Amendment, as more fully described and shown on the floor plan(s)
attached as Exhibit "A" hereto.

         (b)     Third Amendment Space: 5,327 square feet of Rentable Area
located on the third (3rd floor of the Building, subject to adjustment pursuant
to Paragraph 2 of this Third Amendment.

         (c)     Third Amendment Space Renewal Term: Refers to the Third
Amendment Space Renewal Term, if exercised by Tenant pursuant to the terms and
conditions of this Third Amendment.

6.       Except as expressly modified by this Third Amendment, the Lease
remains unchanged and in full force and effect.

         [Signatures to appear on next page.]





                                       8
<PAGE>
IN WITNESS WHEREOF, Landlord and Tenant have executed this Third Amendment as
of the day and year first above written.


                            LANDLORD:
                            ---------

                            HYATT PLAZA LIMITED PARTNERSHIP,
                            a Virginia limited partnership

                            By:      Fair Lakes Hyatt Limited Partnership, a
                                     Virginia general partnership, its general
                                     partner

                            By:      Fair Lakes of Virginia, Inc.,
                                     a Virginia corporation

                            By:   /s/  Milton V. Peterson
                                -------------------------------
                            Name:  Milton V. Peterson
                                 ------------------------------
                            Its:  President
                                 ------------------------------

                            TENANT:
                            -------

                            AMERICAN MANAGEMENT SYSTEMS,
                            INC.,
                            a Delaware corporation

                            By:      /s/  Frank A. Nicolai
                                -----------------------------------
                            Name:    Frank A. Nicolai
                                  --------------------------------
                            Its:  Executive Vice President
                                  -------------------------------
                                  Secretary & Treasurer
                                  -------------------------------




                                       9
<PAGE>

                                   EXHIBIT A

                        THIRD AMENDMENT SPACE FLOOR PLAN

                       [INCLUDES FLOOR PLAN OF PREMISES]





                                       10
<PAGE>
                   FOURTH AMENDMENT TO OFFICE LEASE AGREEMENT



         THIS FOURTH AMENDMENT TO OFFICE LEASE AGREEMENT (this "Fourth
Amendment") is made and entered into as of the 12th day of August, 1996 (the
"Effective Date"), by and between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia
limited partnership ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a
Delaware corporation ("Tenant"), with reference to the following:


                                   RECITALS:


         A.      Pursuant to an Office Lease Agreement dated August 12, 1993,
by and between Landlord and Tenant, as amended by that certain (i) First
Amendment to Office Lease Agreement dated August 31, 1994, (ii) Second
Amendment to Office Lease Agreement dated November 1, 1994 and (iii) Third
Amendment to Office Lease Agreement dated October 2, 1995 (collectively, the
"Lease"), Landlord has leased to Tenant certain premises located at 12701 Fair
Lakes Circle, Fairfax, Virginia, as more particularly described therein.  All
capitalized terms used herein, unless specifically defined, shall have the same
meaning and definition as used in the Lease.

         B.      Landlord and Tenant have agreed to amend the certain terms and
provisions of the Lease as hereinafter set forth.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Landlord and Tenant agree as
follows:

         1.      Landlord and Tenant have agreed to expand the Premises to
include an additional 851 square feet of Rentable Area located on the third
(3rd) floor of the Building (the "Fourth Amendment Space"), commonly known as
Suite 365, as more particularly shown on Exhibit "A" attached hereto and made a
part hereof by this reference.  Base Rent for the Fourth Amendment Space
("Fourth Amendment Space Base Rent") shall be as set forth below:

                 (i)      From August 12, 1996 to August 31, 1997, $18.75 per
         square foot of Rentable Area, or the sum of $15,956.25 per year
         ($1,329.69 per month), and

                 (ii)     From September 1, 1997 to August 31, 1998, $19.22 per
         square foot of Rentable Area, or the sum of $16,356.22 per year
         ($1,363.02 per month).

         2.      Tenant shall lease the Fourth Amendment Space in its "as is"
and "where is" condition, and Landlord shall have no obligation to make any
improvements as a condition of Tenant's acceptance thereof.  Tenant's lease of
Fourth Amendment Space shall commence August 12, 1996 (the "Fourth Amendment
Space Commencement Date") and shall terminate August 31, 1998 (the "Fourth
Amendment Space Expiration Date") (the "Fourth Amendment Space Initial





<PAGE>
Term").  On or before the Fourth Amendment Space Expiration Date, Tenant shall
surrender possession of the Premises to Landlord in accordance with the terms
of the Lease.

         3.      Commencing on January 1, 1997 and thereafter throughout the
Fourth Amendment Space Initial Term, Tenant shall pay on a monthly basis,
without demand, as Additional Rent for the Fourth Amendment Space, .34% of the
amount by which Operating Expenses exceed the Adjusted Base Operating Expenses.
Adjusted Base Operating Expenses shall, for purposes of this Amendment, refer
to the Operating Expenses incurred during the 1996 calendar year.  Such
payments shall be made in accordance with Section 6.01 of the Lease and
Paragraph 3 of the Third Amendment to the Lease.

         4.      Tenant shall have the right to renew and extend the Fourth
Amendment Space Initial Term (the "Fourth Amendment Space Renewal Term") with
respect to the Fourth Amendment Space for one (1) Renewal Term (herein so
called) upon and subject to the following terms and conditions:

                 (a)      Tenant may extend the Fourth Amendment Space Initial
Term for one (1) Renewal Term of three (3) years, such Renewal Term commencing
on September 1, 1998 and expiring on August 31, 2001, by Tenant's giving
written notice thereof to Landlord no later than six (6) months prior to the
expiration of the Fourth Amendment Space Initial Term.  If Tenant does not
exercise its rights to a Renewal Term in a timely manner, Tenant's failure
shall conclusively be deemed a waiver of its rights to a Renewal Term.

                 (b)      The exercise by Tenant of its rights to a Renewal
Term must be made, if at all, by written notice executed by Tenant and
delivered to Landlord on or before the date set forth above.  Once Tenant shall
exercise its rights to a Renewal Term, Tenant may not thereafter revoke such
exercise.  Tenant shall not have the right to exercise a Renewal Term if Tenant
is in Default under the Lease, as amended, either at the time Tenant gives
notice of its election or immediately prior to the commencement of the Renewal
Term.

                 (c)      Tenant shall take the Fourth Amendment Space "as is"
for the Renewal Term and Landlord shall have no obligation to make any
improvements or alterations to the Fourth Amendment Space.

                 (d)      Base Rent per square foot of Rentable Area of the
Fourth Amendment Space for the first year of the Renewal Term shall be the
market rate for Fair Lakes as reasonably determined by Landlord for comparable
size space, and for Leases with comparable terms, conditions and concessions.
Such Base Rate shall be adjusted on September 1 of each subsequent year of the
Renewal Term by multiplying the Base Rent in effect on August 31 by 2.5% and
adding the product to the Base Rent then in effect.  The Adjusted Base Rent
shall be in effect until the next adjustment date.

                 (e)      Subject to subparagraph (d) above, the leasing of the
Fourth Amendment Space for the Renewal Term shall be upon the same terms and
conditions as are applicable for the Fourth Amendment Space Initial Term, and
shall be upon and subject to all of the provisions of





                                       2
<PAGE>
the Lease, including, without limitation, the obligation of Tenant to pay
Tenant's Fourth  Amendment Space Additional Rent under the Lease.

         5.      From and after the Fourth Amendment Space Commencement Date
until the Fourth Amendment Space Expiration Date, the following terms used in
the Lease shall have the following ascribed meanings:

                 (a)      Premises: Refers to the Rentable Area demised to
Tenant by the Lease (set forth therein) and to the space demised to Tenant by
the First Amendment, Second Amendment, Third Amendment and Fourth Amendment
Space, demised to Tenant by this Fourth Amendment.

                 (b)      Fourth Amendment Space: 851 square feet of Rentable
Area located on the third (3rd floor of the Building, subject to adjustment
pursuant to Paragraph 2 of this Fourth Amendment.

                 (c)      Fourth Amendment Space Renewal Term: Refers to the
Fourth Amendment Space Renewal Term, if exercised by Tenant pursuant to the
terms and conditions of this Fourth Amendment.

                 (d)      Rentable Area of the Premises:

<TABLE>
                           <S>                                                <C>
                           Original Lease Space                                84,236 square feet
                           First Amendment Space                                7,926 square feet
                           Second Amendment Space                               5,175 square feet
                           Third Amendment Space                                5,327 square feet
                           Fourth Amendment Space                                 851 square feet
                                                                              -------

                           Total------------------------------------          103,515 square feet
</TABLE>


                 (e)      Tenant's Proportionate Share as to the Fourth
Amendment Space: .34%

         Except as expressly modified by this Fourth Amendment, the Lease
remains unchanged and in full force and effect.





                                       3
<PAGE>
         IN WITNESS WHEREOF, Landlord and Tenant have executed this Fourth
Amendment as of the day and year first above written.




                           LANDLORD:
                           ---------


                           HYATT PLAZA LIMITED PARTNERSHIP,
                           a Virginia limited partnership

                           By: Fair Lakes Hyatt Limited Partnership, a
                               Virginia general partnership, its general partner


                           By: Fair Lakes of Virginia, Inc.,
                               a Virginia corporation
                               its general partner


                           By:
                               -----------------------------------
                           Name:
                                ----------------------------------
                           Its:
                               -----------------------------------



                           TENANT:
                           -------

                           AMERICAN MANAGEMENT SYSTEMS, INC.,
                            a Delaware corporation



                           By:
                              ------------------------------------
                           Name:
                                ----------------------------------
                           Its:
                               -----------------------------------





                                       4
<PAGE>
                                   EXHIBIT A

                       FOURTH AMENDMENT SPACE FLOOR PLAN


                    [INCLUDES FLOOR PLANS OF THE PREMISES]





                                       5
<PAGE>
                   FIFTH AMENDMENT TO OFFICE LEASE AGREEMENT


         THIS FIFTH AMENDMENT TO OFFICE LEASE AGREEMENT (this "Fifth
Amendment") is made and entered into as of the 30th day of September, 1996 (the
"Effective Date"), by and between HYATT PLAZA LIMITED PARTNERSHIP, a Virginia
limited partnership ("Landlord"), and AMERICAN MANAGEMENT SYSTEMS, INC., a
Delaware corporation ("Tenant"), with reference to the following:


                                   RECITALS:


         A.      Pursuant to an Office Lease Agreement dated August 12, 1993,
by and between Landlord and Tenant, as amended by that certain (i) First
Amendment to Office Lease Agreement dated August 31, 1994, (ii) Second
Amendment to Office Lease Agreement dated November 1, 1994, (iii) Third
Amendment to Office Lease Agreement dated October 2, 1995 and (iv) Fourth
Amendment to Office Lease Agreement dated August 12, 1996 (collectively, the
"Lease"), Landlord has leased to Tenant certain premises located at 12701 Fair
Lakes Circle, Fairfax, Virginia, 22033, as more particularly described therein.
All capitalized terms used herein, unless specifically defined, shall have the
same meaning and definition as used in the Lease.

         B.      Landlord and Tenant have agreed to amend the certain terms and
provisions of the Lease as hereinafter set forth.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, Landlord and Tenant agree as
follows:





<PAGE>

         1.      As an exercise of Tenant's Right of First Refusal Option,
Landlord and Tenant have agreed to expand the Premises to include an additional
3,350 square feet of Rentable Area located on the first (1st) floor of the
Building (the "Fifth Amendment Space"), commonly known as Suite 160, as more
particularly shown on Exhibit "A" attached hereto and made a part hereof by
this reference.  Base Rent for the Fifth Amendment Space ("Fifth Amendment
Space Base Rent") shall be as set forth below:

                 (i)      From October 1, 1996 to September 30, 1997, $21.00
         per square foot of Rentable Area, or the sum of $70,350.00 per year
         ($5,862.50 per month), and

                 (ii)     From October 1, 1997 to September 30, 1998, $21.63
         per square foot of Rentable Area, or the sum of $72,460.50 per year
         ($6,038.38 per month).

         2.      Tenant shall lease the Fifth Amendment Space in its "as is"
and "where is" condition, and Landlord shall have no obligation to make any
improvements as a condition of Tenant's acceptance thereof.  Tenant's lease of
Fifth Amendment Space shall commence October 1, 1996 (the "Fifth Amendment
Space Commencement Date") and shall terminate September 30, 1998 (the "Fifth
Amendment Space Expiration Date") (the "Fifth Amendment Space Initial Term").
On or before the Fifth Amendment Space Expiration Date, Tenant shall surrender
possession of the Premises to Landlord in accordance with the terms of the
Lease.

         3.      Commencing on January 1, 1998 and thereafter throughout the
Fifth Amendment Space Initial Term, Tenant shall pay on a monthly basis,
without demand, as Additional Rent for the Fifth Amendment Space, 1.33% of the
amount by which Operating Expenses exceed the Adjusted Base Operating Expenses.
Adjusted Base Operating Expenses shall, for purposes of





                                       2
<PAGE>
this Amendment, refer to the Operating Expenses incurred during the 1997
calendar year.  Such payments shall be made in accordance with Sections 6.01
and 6.02 of the Lease.

         4.      Tenant shall have the right to renew and extend the Fifth
Amendment Space Initial Term (the "Fifth Amendment Space Renewal Term") with
respect to the Fifth Amendment Space for one (1) Renewal Term (herein so
called) upon and subject to the following terms and conditions:

                 (a)      Tenant may extend the Fifth Amendment Space Initial
Term for one (1) Renewal Term of three (3) years, such Renewal Term commenting
on October 1, 1998 and expiring on September 30, 2001, by Tenant's giving
written notice thereof to Landlord on or before April 1, 1998.  If Tenant does
not exercise its rights to a Renewal Term in a timely manner, Tenant's failure
shall conclusively be deemed a waiver of its rights to a Renewal Term.

                 (b)      The exercise by Tenant of its rights to a Renewal
Term must be made, if at all, by written notice executed by Tenant and
delivered to Landlord on or before the date set forth above.  Once Tenant shall
exercise its rights to a Renewal Term, Tenant may not thereafter revoke such
exercise.  Tenant shall not have the right to exercise a Renewal Term if Tenant
is in Default under the Lease, as amended, either at the time Tenant gives
notice of its election or immediately prior to the  commencement of the Renewal
Term.

                 (c)      Tenant shall take the Fifth Amendment Space "as is"
for the Renewal Term and Landlord shall have no obligation to make any
improvements or alterations to the Fifth Amendment Space.





                                       3
<PAGE>
                 (d)      Base Rent per square foot of Rentable Area of the
Fifth Amendment Space for the first year of the Renewal Term shall be at the
rate of $22.28 per square feet for the Fifth Amendment Space.  Such Base Rate
shall be adjusted on October 1 of each subsequent year of the Renewal Term by
multiplying the Base Rent in effect on September 30 by 3.0% and adding the
product to the Base Rent then in effect.  The Adjusted Base Rent shall be in
effect until the next adjustment date.

                 (e)      Subject to subparagraph (d) above, the leasing of the
Fifth Amendment Space for the Renewal Term shall be upon the same terms and
conditions as are applicable for the Fifth Amendment Space Initial Term, and
shall be upon and subject to all of the provisions of the Lease, including,
without limitation, the obligation of Tenant to pay Tenant's Fifth Amendment
Space Additional Rent under the Lease.

         5.      From and after the Fifth Amendment Space Commencement Date
until the Fifth Amendment Space Expiration Date, the following terms used in
the Lease shall have the following ascribed meanings:

                 (a)      Premises: Refers to the Rentable Area demised to
Tenant by the Lease (set forth therein) and to the space demised to Tenant by
the First Amendment, Second Amendment, Third Amendment, Fourth Amendment and
Fifth Amendment Space, demised to Tenant by this Fifth Amendment.

                 (b)      Fifth Amendment Space: 3,350 square feet of Rentable
Area located on the first (1st) floor of the Building.





                                       4
<PAGE>
                 (c)      Fifth Amendment Space Renewal Term: Refers to the
Fifth Amendment Space Renewal Term, if exercised by Tenant pursuant to the
terms and conditions of this Fifth Amendment.

                 (d)      Rentable Area of the Premises:

<TABLE>
                                  <S>                                          <C>
                                  Original Lease Space                          84,236 square feet
                                  First Amendment Space                          7,926 square feet
                                  Second Amendment Space                         5,175 square feet
                                  Third Amendment Space                          5,327 square feet
                                  Fourth Amendment Space                           851 square feet
                                  Fifth Amendment Space                          3,350 square feet
                                                                               -------
                                  Total ----------------------------------     106,865 square feet
</TABLE>

                 (e)      Tenant's Proportionate Share:

<TABLE>
                                  <S>                                                       <C>
                                  Original Premises                                         33.37%
                                  First Amendment Space                                      3.14%
                                  Second Amendment Space                                     2.05%
                                  Third Amendment Space                                      2.11%
                                  Fourth Amendment Space                                      .34%
                                  Fifth Amendment Space                                      1.33%
                                                                                            ------
                                  Total........................................             42.34%
</TABLE>

                 (f)      Base Year:

<TABLE>
                                  <S>                                                         <C>
                                  Original Premises                                           1994
                                  First Amendment Space                                       1995
                                  Second Amendment Space                                      1995
                                  Third Amendment Space                                       1996
                                  Fourth Amendment Space                                      1996
                                  Fifth Amendment Space                                       1997
</TABLE>

         6.      Except as expressly modified by this Fifth Amendment, the
Lease remains unchanged and in full force and effect.


                     [Signatures appear on following page]





                                       5
<PAGE>
         IN WITNESS WHEREOF, Landlord and Tenant have executed this Fifth
Amendment as of the day and year first above written.


                              LANDLORD:
                              --------

                              HYATT PLAZA LIMITED PARTNERSHIP,
                              a Virginia limited partnership

                              By:     Fair Lakes Hyatt Limited Partnership, a
                                      Virginia general partnership, its general
                                      partner

                              By:     Fair Lakes of Virginia, Inc.,
                                      a Virginia corporation
                                      its general partner


                              By:                [SIG]
                                      -----------------------------------
                              Name:
                                      -----------------------------------
                              Its:
                                      -----------------------------------


                              TENANT:
                              ------

                              AMERICAN MANAGEMENT SYSTEMS,
                              INC., a Delaware corporation


                              By:     /s/ Frank A. Nicolai
                                      -----------------------------------
                              Name:
                                      -----------------------------------
                              Its:
                                      -----------------------------------


[FOLLOWED BY FLOOR PLANS ATTACHED AS EXHIBIT A]





                                       6
<PAGE>
                   FIFTH AMENDMENT TO OFFICE LEASE AGREEMENT



         THIS FIFTH AMENDMENT TO OFFICE LEASE AGREEMENT (the "Fifth Amendment")
is made and entered into this 30th day of November, 1996, but effective for all
purposes on the Assignment Date (hereinafter defined) by and among HYATT PLAZA
LIMITED PARTNERSHIP, a Virginia limited partnership, and AMERICAN MANAGEMENT
SYSTEMS, INC., a Delaware corporation (hereinafter sometimes referred to as
"Assignee" and/or "Tenant") with reference to the following:


                                   RECITALS:


         A.      Pursuant to the terms of that certain Office Lease Agreement
dated May 21, 1990, as amended by First Amendment dated July 12, 1990, Second
Amendment dated July 27, 1990, Third Amendment dated April 18, 1991 and Fourth
Amendment dated September 22, 1994 (collectively hereinafter referred to as the
"Lease"), Landlord leased to Trident Data Systems, Inc., a California
corporation ("Original Tenant") that certain premises (the "Premises") more
particularly described therein.  All capitalized terms used in this Fifth
Amendment which are not defined herein, shall have the same meaning and
definition as used in the Lease.

         B.      Pursuant to that certain Assignment of Office Lease Agreement
dated __________, 1996 (the "Assignment") by and between Original Tenant and
Assignee, Original Tenant, with Landlord's consent, has assigned to Assignee
all of its right, title and interest in and to the Lease (as defined in the
Assignment).  The Assignment contains certain provisions which permit the
Original Tenant and the Assignee to terminate the Assignment should certain
events occur.  The date that all of the rights of Assignee and the Original
Tenant to terminate the Assignment cease and the assignment of the Lease to the
Assignee becomes effective is hereinafter referred to as the "Assignment Date."

         C.      The parties have agreed to amend certain terms and provisions
of the Lease, as of the Assignment Date.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

         1.      From and after the Assignment Date, any and all references in
the  Lease to the term Tenant shall mean and refer to the Assignee.

         2.      As of the Assignment Date, Tenant exercises its right of
renewal set forth in Rider No. 4 of the Lease.  As a result of the foregoing
exercise, the Term of the Lease has been extended for an additional six (6)
years, two (2) months (the "Extension Term"), commencing on January 1, 1998
(the "Extension Commencement Date") and expiring on February 29, 2004 (the
"Expiration Date").  The Base Rent for the Extension Term shall be $413,462.60
per year ($34,455.22 per month), based upon $20.60 times 20,071, the number of
square feet of Rentable Area in the Premises.  The Base Rent for the Extension
Term shall be increased by 3% annually on each





<PAGE>
January 1st throughout the Extension Term, with the first increase occurring on
January 1, 1999.  During the Extension Term, the Base Operating Expenses Amount
and the Base Real Estate Taxes Amount shall be equal to Tenant's proportionate
share of the actual Operating Expenses and Base Real Estate Taxes incurred by
Landlord with respect to the Building during calendar year 1998.

         3.      Landlord and Tenant agree that Tenant shall lease the Premises
in its "as is" and "where is" condition during the Extension Term and Landlord
shall not be obligated to make any improvements whatsoever to the Premises as a
condition of Tenant's extension of the Lease, nor shall Landlord be obligated
to provide Tenant any allowances.

         4.      As of the Assignment Date, Article 12 - Alterations shall be
deleted in its entirety, and replaced with the following:

                 "After the initial Leasehold Improvements are completed,
         Tenant shall not, at any time during the Term, without Landlord's
         prior written consent, make any Alterations (hereinafter defined) to
         the Premises.  Should Tenant desire any Alterations, Tenant agrees to
         submit all plans and specifications for same to Landlord for
         Landlord's written approval, before beginning such work and Landlord's
         approval shall not be unreasonably withheld, conditioned or delayed.
         Provided Tenant has supplied Landlord with information and plans for
         the Alterations which reasonably details the nature and scope of the
         same, Landlord's failure to respond to Tenant's request for approval
         within ten (10) business days after receipt of the information, plans
         and request for approval, shall be deemed to be Landlord's approval of
         the same.  Landlord shall not be considered as unreasonably
         withholding its approval by refusing to consent to any Alterations
         which alter the exterior appearance of the Building, or the public
         lobbies, corridors, or common areas thereof, which will or are likely
         to cause any weakening of any part of the structure of the Premises or
         Building or which may cause damage or disruption to any Building
         system and such damage or disruption is not repaired as part of the
         Alterations.  Upon Tenant's receipt of Landlord's written approval,
         Tenant may proceed with the construction of the approved Alterations,
         but only so long as they are in substantial compliance with the plans
         and specifications approved by Landlord and provisions of this Article
         12.  Additionally, the construction of any alterations (regardless of
         whether or not Landlord's prior approval of the work is required by
         this Lease), the alterations themselves, or any maintenance thereof
         shall comply with all building, safety, fire, plumbing, electrical and
         other codes and governmental and insurance requirements, and shall not
         require an amount of water, electricity, gas, heat, ventilation, or
         air-conditioning which exceeds reasonable level of consumption for a
         modem business office unless prior written arrangements reasonably
         satisfactory to Landlord are made with respect thereto.  All
         alterations shall be made at Tenant's expense, either by Tenant's
         contractors which have been approved in advance by Landlord or at
         Tenant's option, by Landlord's contractors on terms reasonably
         satisfactory to Tenant.  In the event Landlord actually constructs the
         alterations or is retained by Tenant to supervise or manage  the
         construction by contractors selected by Tenant and approved by
         Landlord, then Tenant shall pay to Landlord a fee equal to ten percent
         (10%) of the actual costs of such work, such fee to cover Landlord's
         overhead related to the work, including, but not limited to,
         Landlord's review of the plans and specifications, coordination of the





                                       2
<PAGE>
         work, consultation with professionals regarding the work, and general
         administration allocable to the work.  The foregoing fee will not be
         charged in circumstances where Landlord has merely approved the
         Alterations.  All such construction shall be completed promptly and in
         a good and workmanlike manner and shall be performed in compliance
         with the lien provisions set forth in Article 13 of the Lease.

                 As used in the Lease, the term Alterations refers to work
         performed after the completion of the initial Leasehold Improvements
         which would reasonably be considered major construction, renovations
         or changes to the Premises, having a material impact on the appearance
         of the Premises or to other portions of the Building, or would
         otherwise have a material impact (structural, mechanical, operational
         or otherwise) upon the Building, and/or the total cost of the
         construction, renovations or changes is more than $75,000.00.
         Alterations do not include, by way of example, by hanging of pictures,
         the movement of furniture and flexible space walls or partitions, or
         the painting of the interior of the Premises.  Prior to commencing any
         alterations, Tenant will coordinate with Landlord so as to schedule
         the movement of men, material and equipment through the Building's
         common  areas in a manner which does not unreasonably interrupt the
         normal Building operations and the use and enjoyment of the Building
         by other tenants therein.

                 All existing Improvements and improvements to the Premises
         constructed by Tenant and paid for by Tenant from funds supplied by
         Landlord either in the form of allowances or credits shall be and
         remain the Landlord's property, and shall not be removed from the
         Premises.  Tenant shall have the right, upon expiration of the Term,
         to remove, at Tenant's expense, all alterations to the Premises (other
         than the Existing Improvements and the improvements or alterations
         paid by allowances granted by Landlord); specialized trade fixtures or
         other systems or items installed by Tenant pursuant to Article 12 of
         the Lease, and; moveable trade fixtures.  Tenant agrees to remove, at
         Tenant's expense, all of its furnishings, furniture and movable
         personal property by the Expiration Date.  Tenant will promptly
         restore any damage to the Premises or Building caused by its removal
         of its property."





                                       3
<PAGE>

         5.      From and after the Extension Commencement Date, the following
terms as defined in the Lease shall have the following meanings:

                 (a)      Term: Thirteen (13) years, five (5) months and
seventeen (17) days.

                 (b)      Expiration Date:  February 29, 2004.

                 (c)      Base Rent:$413,462.60 per year ($34,455.22 per
month), which amount is based upon $20.60 per square foot of Rentable Area in
the Premises, effective as of the Extension Commencement Date, as adjusted
pursuant to Section 5.02 of  the Lease, as modified herein.

                 (d)      Adjustment Factor:  3.0%

                 (e)      Tenant's Proportionate Share:8.05%

         6.      From and after the Assignment Date, Section 5.02 of the Lease
shall be deleted and the following inserted in lieu thereof.

                          "(a)    During the Term of this Lease, the Base Rent
         shall be adjusted on January 1, 1999 and the first day of January
         thereafter pursuant to this Section.  The dates described in this
         Section for computing the adjustment in Base Rent are hereinafter
         sometimes referred to collectively as "Rental Adjustment Dates" and
         singularly as a "Rental Adjustment Date".  All adjustment to Base Rent
         required by this Section 5.02 shall be made as hereinafter described:

                 (1)      On the first Rental Adjustment Date, the Base Rent
         shall be multiplied by the Adjustment Factor and the amount computed
         shall be added to the Base Rent as of the first Rental Adjustment Date
         and the resulting sum shall be the adjusted Base Rent (hereinafter the
         "Adjusted Rent") to be paid by the Tenant to Landlord, in advance,
         without demand, in equal monthly installments, on the first day of
         each calendar month until the next Rental Adjustment Date.

                 (2)      On the second Rental Adjustment Date and on every
         Rental Adjustment Date throughout the term of this Lease, the Adjusted
         Rent payable in the year immediately preceding the Rental Adjustment
         Date in question shall be multiplied by the Adjustment Factor and the
         amount computed shall be added to the Adjusted Rent for the year
         immediately preceding the Rental Adjustment Date and the resulting sum
         shall be the Adjusted Rent for that rental year to be paid by the
         Tenant to Landlord, in advance, without demand, in equal monthly
         installments, on the first day of each calendar month until the next
         Rental Adjustment Date.

                          (b)     Landlord shall provide Tenant with written
         notice of each adjustment pursuant to Section 3.02(b), which notice
         shall provide the basis upon which such adjustment has been
         calculated; provided, however, that if for any reason Landlord





                                       4
<PAGE>
         does not notify Tenant of the amount of such adjustment until after
         any Rental Adjustment Date, Tenant shall continue to pay the Base Rent
         or Adjusted Rent, as the case may be, payable prior to the Rental
         Adjustment Date, and Tenant, within five (5) days following Landlord's
         delivery of written notice of such adjustment shall pay to Landlord
         in a lump sum the amount of any increase in the Base Rent resulting
         from such adjustment for all months in the existing calendar year
         prior to and including the month 'in which such notice of adjustment
         is received and during the remainder of such year Tenant shall pay to
         Landlord the Adjusted Rent as set forth in such notice."


         7.      Section 1.01.6 and all references to Base Net Rent shall be
deleted.

         8.      This Fifth Amendment shall be effective only upon the
Assignment Date.  Should, for any reason, either the Original Tenant or the
Assignee terminate the Assignment, then this Fifth Amendment shall be null and
void and the Original Tenant shall continue to occupy the Premises pursuant to
the terms of the Lease, unmodified, and in full force and effect.





                                       5
<PAGE>
                 IN WITNESS WHEREOF, Landlord and Tenant have executed this
Fifth Amendment as of the day and year first above written.




                               LANDLORD:
                               ---------

                               HYATT PLAZA LIMITED PARTNERSHIP,
                               a Virginia limited partnership

                               By:  Fair Lakes Hyatt Limited Partnership, a
                                    Virginia general partnership, its
                                    general partner


                               By:  Fair Lakes of Virginia, Inc.,
                                    a Virginia corporation
                                    its general partner

                               By:   /s/ Milton V. Peterson
                                  --------------------------------
                               Name: Milton V. Peterson
                                     -----------------------------
                               Its:  President
                                     -----------------------------



                               ASSIGNEE/TENANT:
                               ----------------

                               AMERICAN MANAGEMENT SYSTEMS, INC.,
                                 a Delaware corporation, successor-in-interest
                                 to Trident Data Systems, Inc., a California
                                 corporation


                               By: /s/ Frank Nicolai
                                   --------------------------------
                               Name:
                                     ------------------------------
                               Its:
                                   --------------------------------





                                       6
<PAGE>
                              ASSIGNMENT OF LEASE

         THIS ASSIGNMENT OF LEASE (the "Assignment") is made and entered into
this 30th day of September, 1996 by and between Trident Data Systems, Inc. (the
"Assignor") and American Management Systems, Inc. (the "Assignee"), with
reference to the following:

                                   RECITALS:

         A.      Pursuant to a Lease Agreement, dated May 17, 1990 as amended
by the First Amendment dated July 12, 1990, the Second Amendment dated July 27,
1990, the Third Amendment dated April 18, 1991 and the Fourth Amendment dated
September 22, 1994 (collectively the "Lease") by and between Assignor and Hyatt
Plaza Limited Partnership (the "Landlord"), Assignor leased certain premises
totaling 20,071 rentable square feet more particularly described therein.

         B.      Assignor desires to assign unto the Assignee all of the
Assignor's rights, title and interest under the Lease.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereby agree as
follows:

         1.      Effective as of February 1, 1997 (the "Effective Date")
Assignor assigns all of its rights and obligations under the Lease and Assignee
accepts such assignment of





                                  Page 1 of 4
<PAGE>
all the Assignor's rights and obligations thereunder.  In the event the
Premises are not made available to the Assignee by the Effective Date, the
Assignor shall pay the Assignee a penalty of $1,219.87 for each day the
Premises are not available beyond the Effective Date.  In addition, if the
Premises are not made available to the Assignee by March 1, 1997, the Assignee
shall have the option to cancel the Assignment.

         2.      From and after the Effective Date, Assignee will perform all
of the provisions to be performed under the Lease by Assignor and Landlord
shall be entitled to all the rights, benefits and rentals accruing thereunder.

         3.      The Assignor shall pay the Assignee $80,000 in two equal
installments of $40,000 payable on January 1, 1997 and March 1, 1997.  In
addition, the Assignor shall pay a brokerage commission to Cushman & Wakefield
equal to $12,142.96 as the Assignee's broker representative.  The amounts due
from Assignor to Assignee under this paragraph 3 are solely the obligation of
the Assignor and shall under no circumstances have any effect upon the Lease or
this Assignment.

         4.      The Assignor represents and warrants that the monthly base
rent for the Premises will be $36,596.12 per month through December 31, 1997.
In addition, the Assignor currently pays $1,610.24 per month in estimated real
estate tax and operating expense passthroughs which is subject to adjustment
based upon actual costs pursuant to Article 6 of the Lease.





                                  Page 2 of 4
<PAGE>
         5.      This Assignment is contingent on Pacific Mutual Life Insurance
Company countersigning a lease with Trident Data Systems, Inc. for office space
at 10455 White Granite Drive, Oakton, Virginia.  In the event the Assignor has
not satisfied the contingency within ten (10) days of the date hereof, then the
Assignor shall have the option to rescind this Assignment at any time within
twenty (20) days thereafter.

         6.      Assignor, Assignee and Landlord acknowledge and agree that the
Assignee shall have no rights to the security deposit under the Lease and that
the security deposit will be returned to the Assignor by Landlord in accordance
with the terms of a separate agreement.

         WITNESS the following signatures and seals of Assignor and Assignee
made as of the date first above written.


                                  ASSIGNOR:
                                  --------

                                  TRIDENT DATA SYSTEMS, INC.

                                  By:    /s/ David A. Muckley
                                     ---------------------------------
                                  Name:  David A. Muckley
                                      --------------------------------
                                  Its:  President & CEO
                                        ------------------------------

                                  ASSIGNEE:
                                  --------

                                  AMERICAN MANAGEMENT SYSTEMS, INC.

                                  By:   /s/ Frank A. Nicolai
                                     ---------------------------------
                                  Name:
                                      --------------------------------
                                  Its:
                                     ---------------------------------





                                  Page 3 of 4
<PAGE>

         The undersigned, the Landlord of the above referenced Lease, hereby
executes this Assignment solely to evidence its consent to the assignment by
the Assignor to the Assignee.  The undersigned reserves its rights under the
Lease to consent and approve any future assignment of the Lease.  The consent
by Landlord shall not be deemed a release of the Assignor of the Tenant's
obligations under the Lease accruing prior to the Effective Date of this
Assignment.  Upon the Assignor surrendering possession by the Effective Date,
the Assignor and Landlord shall have no further obligations to each other under
the Lease except for the following provisions which expressly state that such
provisions shall survive termination of the Lease: Articles 5.04, 6.01 and
6.02.

                           LANDLORD:
                           --------

                           By:  Fair Lakes Hyatt Limited Partnership*, its g.p.
                           By:  Fair Lakes of Virginia, Inc.**, its gen. partner

                           By:    /s/ Milton V. Peterson
                              ---------------------------------
                           Name: Milton V. Peterson
                           Its: President

                           *   a Virginia limited partnership
                           **  a Virginia corporation

                           By:
                              -----------------------------
                           Name:
                                ----------------------------
                           Its:
                               -----------------------------


                           By:
                              ------------------------------
                           Name:
                                -----------------------------
                           Its:
                               ------------------------------





                                  Page 4 of 4

</TEXT>
</DOCUMENT>
