How do weapon pylons attach to a fighter's wings?

The pylons are not just for weapons; the term used for the Typhoon aircraft is the Wing Pylon Station Unit (WPSU) and some of those are designed to be able to carry external fuel tanks.

Some aircraft (such as the vernerable F-4 Phantom II) had 4 wing pylons which were more or less permanently attached (unless they were defective in which case they could be replaced); certainly in the years I worked on them I never saw an aircraft without all 4 pylons.

Other aircraft (such as the Typhoon) have pylons that are not necessarily all fitted
(there are locations for up to 8 wing pylons)

Here is a fit using only 6 of the pylons and all 5 fuselage hard points:

Here is a different setup using all 8 wing pylons:

Source

The attachment is relatively simple (it has to be as it can be a hangar operation for operational fit); the pylons are physically attached with mechanical mounting and electrical connectivity (to actually operate the items being carried); the pylons that can take external tanks also have fuel feed points.

The pylons also have communication links for the aircradt to 'talk' the whatever happens to be fitted on the pylons (the data could be commands, video feed, sensor data, stores readiness - whatever is required for a particular type of store on the pylon)

It is important to note that the all the hard points are considered safety critical as you do not want to fire / jettison something when not commanded and you do want that at the appropriate time.

The inner structure of the pylons is almost completely full (very little space unused) which keeps the unit as small as possible (which enhances its ability to withstand aerodynamic forces) and as light as possible.

The electronics within the pylons are somewhat expensive as the internal temperature can be as low as -50C or lower at high altitudes; the leading edge is a low drag surface to minimise heating by air friction.

Different pylons will have slightly different attachment methods but they all need to withstand the aerodynamic forces and provide electrical and communication functionality.

Update

Here is a close up of an F35 pylon (designed for air to air weapons):

Source

The mounting bolt position is clearly shown (there is another on the other side of the pylon). The pylon fits into an acceptor slot and all the various connections are made simply by placing the pylon in the correct position and sliding it in. The direction of sliding is from the front so aerodynamic pressure keeps it in position.

Interesting fact. One fine day I was working on the flight line at RNAS Yeovilton when an american F-4 flew over; he was doing a bit of hot-dogging. The aircraft had two external wing mounted Sargent Fletcher fuel tanks and when he did a high G pullup, the tanks separated from the wing pylons and landed on a roundabout in the middle of the road.

This is one of the issues with wing pylons and stores; they impose a g limit on maneuvering or things literally break away.

I understand his boss was not at all pleased.


Why is the V1-speed callout automated in modern commercial aircraft while VR is not?

from my experience (A310, A320 family, A340), V1 and VR speeds are often very close together, sometimes they even are the same.

The automatic callout system can only output one signal at a time; during landings, one can often hear the decreasing radar altitude callouts being overlapped. Therefore, the VR callout would often supersede the - more safety relevant - V1 callout.


What rules would allow a pilot to refuse a passenger's boarding?

The regulation that springs immediately to mind is FAR 91.17(b):

  Except in an emergency, no pilot of a civil aircraft may allow a person who appears to be intoxicated or who demonstrates by manner or physical indications that the individual is under the influence of drugs (except a medical patient under proper care) to be carried in that aircraft.

i.e. "If you get yourself blind stinking drunk at the airport bar, or you've been doing lines of cocaine in the airport bathroom you are not getting on the plane because the FAA says I can't let you."

For other cases you need to head over to 49 USC 44902, which deals with Refusal to transport passengers and property for "air carriers" (FAR part 121, and I believe 135 operations are covered by this bit of the US Code). The most relevant text is:

  (b) Permissive Refusal.
  Subject to regulations of the Under Secretary, an air carrier, intrastate air carrier, or foreign air carrier may refuse to transport a passenger or property the carrier decides is, or might be, inimical to safety.

Most air carriers vest the captain with the decision-making authority here: If the captain determines that a passenger may be "inimical to safety" they can refuse to fly the passenger.  There are some restrictions on that authority - notably that the basis for the decision can't be "discriminatory" - which are scattered about in 14CFR (the FARs) and 49USC (Transportation), as well as case law. The FAA has issued at least one legal interpretation discussing this in more detail.

For commercial (or non-commercial) operations under part 91 I wasn't able to find anything specific in 14CFR or 49USC, but in those cases the general consensus seems to be that the PIC has at least the level of authority granted under 49USC44902 - if not broader authority (i.e. if you're going on a personal flight you could refuse to take someone along because you don't like their shoes, and if someone hires you for a commercial flight you could refuse the job if they were acting sketchy).


The A320 has an auto mode that will do the following:

Center tank will empty first.
The inner wing tanks will empty until they reach 750 kg in each.
The outer tank transfer valves will open and remain open allowing fuel to flow to the inner tanks.
The center tank pump will stop 5 minutes after low level is reached and remain stopped until the inner wing tank reaches the underfill sensor (approx. 500 kg) at which point it will restart.

The center tank pumps can be switched to manual mode.
The wing tanks can be turned off manually.
The cross feed valve is also operated manually.

source: A320 FCOM


Why is this chart called a Short Field Effort Takeoff Ground Roll and not simply a Short Field Takeoff Ground Roll?

I think it is used in the same meaning as the maximum effort takeoff/landing (similar to @mins comment above). Maximum effort takeoff is used to reduce the ground roll/obstacle clearance distance. Maximum effort landing (or assault landing, as it is called) is used to reduce the ground roll after landing. This is mostly used for military aircraft, which may have to operate from small, improvised forward air strips.

This is alluded to in the PA-44-180 manual:

  In certain short field takeoff efforts when the shortest possible ground roll and the greatest clearance distance over a 50 ft. obstacle is desired, a flap setting of 25° is recommended.

This can also be figured out from the charts themselves. For Pressure altitude of 680', OAT of 8$^{\circ}C$, 8kt headwind and 3430 lb TOW, the normal TO roll is 920', while the short filed effort TO roll is only 800'. For the same specifications, the total distance over a 50' barrier using normal procedures is 1750', while using short field effort, it reduces to 1280' (All figures from the manual).

You can see a C130J demonstrating max-effort TO and landing here.


Is there a surface of a commercial jet exposed to air flow at speed near Mach 1?

Of course! If you check the wikipedia page the Critical Mach Number of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound, but does not exceed it.
The Drag Divergence Mach Number is usually bigger than the Critical Mach Number, it means that at that speed there are big surfaces exposes to speed of air larger than 1.

It can happen because the figure of an airplane is shaped in order to avoid shock waves with flow and to postpone the maximum as possible the Drag divergence Mach number (in order to have a greater cruise speed).

Where?
On the upper part of the wings, where the flow is accelerated in order to produce lift.

Clarification about engines (thanks to the help of one of the comments):

The flow from a jet engine has a speed about double of the cruise speed of the airplane. Anyway the outflow from an airliner jet engine is much hotter than the surrounding air, so the speed of sound in this gas stream is much higher; its Mach number is still subsonic.


What was Boeing's competitor to the C-5?

In 1964 the US Air Force awarded study contracts for a new cargo aircraft to Boeing, Douglas and Lockheed. The aircraft was called CX-HLS. ( cargo experimental - heavy logistics system)

Lockheed won with the C-5A design. Boeing's design was never built but would have looked like this:

source: Widebody Aircraft Chronology

Source: Boeing archives

Source:TDPRI.COM


What is the relation between altitude and vertical speed?

The graphic is attributed to Flightradar24. Flightradar24 relies on transmitted data from the plane (via ADS-B usually) and it is not always perfect. See: Why do aircraft on Flight Radar 24 jump around randomly sometimes?

Back to your question, decreasing vertical speed (V/S) is not descending, it's just the rate of climb is becoming shallower, but still positive.

Factors that can cause the illustrated drop:

Bad data from Flightradar24.
Insufficient reading resolution (thanks @bogl).
Imperfect reading by the plane (see below).

V/S and altitude are measured by the static ports, if the plane's attitude is not ideal, say the plane is moving sideways slightly, each static port on each side will read differently.

The measured quantities are also different, one is a rate of change, and one is absolute reading, this may cause the V/S to lag behind the altimeter.


How can I legally organise a high school football game flyover in Delta airspace?

First, the high school has no authority over the national airspace system so any 'permission' is meaningless, at least from the aviation point of view. I assume you want to coordinate with the school for timing and so on, but they can't approve or deny your flight, or tell you what altitude to fly at. (I'm ignoring any school disciplinary issues here, e.g. you're a student and the event is during class time.)

Second, the class D controllers probably won't mind provided that you give them some advance notice (call them a week or two in advance) and keep talking to them while you're in the air. Similar flights happen all the time in controlled airspace for photography and other reasons, so unless the stadium is right under final approach it shouldn't be a big deal.

Third, 14 CFR 91.119(b) says that the minimum altitude in this case would be (my emphasis):

  Over any congested area of a city, town, or settlement, or over any
  open air assembly of persons, an altitude of 1,000 feet above the
  highest obstacle within a horizontal radius of 2,000 feet of the
  aircraft

(And don't forget that 119(a) requires you be able to make an emergency landing without endangering people on the ground.)

If you want to fly lower than that then you need a waiver from your local FSDO, but it's entirely at their discretion so you would need to convince them that you have a good, safe plan.

Finally, it's worth saying that there are a bunch of safety issues associated with doing things like this so if you do go ahead make sure you have a good plan and you stick to it. In particular, decide your minimum altitude and airspeed in advance and don't go below them under any circumstances.


Who authorizes low visibility takeoff operations for airlines, and what is required?

The Part 121 regulation that governs low visibility takeoffs are specified in 14 CFR 121.651.  It references company OpSpecs and 91.175 and Part 97:

"Standard" takeoff minimums are specified in 14 CFR 91.175 and would be the highest of:

Non-standard takeoff minimums specified on the airport charts (FAR 97)
For aircraft, other than helicopters, having two engines or less — 1 statute mile visibility.
For aircraft having more than two engines — 1⁄2 statute mile visibility.
For helicopters — 1⁄2 statute mile visibility.

OpSpec C056 is issued to all 121 carriers, and basically just spells out the "standard" takeoff minimums that I listed above, and specifies that RVR must be used if it is available on the runway.

OpSpec C078 is normally issued and allows taking off with lower than standard visibility as long as the airport doesn't already have published higher than standard takeoff minimums.  This is a fairly involved OpSpec with several optional paragraphs, and operators may be approved for takeoff operations down to and including 300 RVR.  For those not familiar with the term, RVR (Runway Visual Range) is the distance that a pilot can see down the runway, measured by automatic equipment,  and is measured in feet in the US.

It offers approvals for the following visibilities:

1/4 SM / RVR 1600:

Touchdown zone RVR (or mid RVR if touchdown zone is inop) is controlling:
Requires "runway markings or runway lighting provide pilots with adequate visual reference to continuously identify the takeoff surface and maintain directional control throughout the takeoff run." (Basically as long as the pilot feels comfortable, but specifically mentions HIRL, CL, and RCLM as okay.)

RVR 1000 (optional)

Touchdown zone RVR and rollout RVR (A mid-RVR report may be substituted for either if they are inop, but still must have two systems) are both controlling
Requires Runway Centerline Lights (CL)

RVR 500 (optional)

Touchdown zone RVR, mid RVR, and rollout RVR are all controlling (one may be inop)
Requires Operative runway centerline lights (CL)
Requires Runway centerline markings (RCLM)

RVR 300 (optional)

Requires a takeoff guidance system
Requires operative high intensity runway lights (HIRL)
Requires operative runway centerline lights (CL)
Requires serviceable runway centerline markings (RCLM)
Front course guidance from the localizer (if applicable to the system used)
Crosswind less than 10 knots
Touchdown zone RVR, mid RVR, and rollout RVR are all controlling (one may be inop)
Requires special training requirements for both the PIC and SIC
Taxiways with operative taxiway centerline lighting must be available

Regulations/Sample OpSpecs

  §121.651 Takeoff and landing weather minimums: IFR: All certificate
  holders.

  (a) Notwithstanding any clearance from ATC, no pilot may begin a
  takeoff in an airplane under IFR when the weather conditions reported
  by the U.S. National Weather Service, a source approved by that
  Service, or a source approved by the Administrator, are less than
  those specified in—

  (1) The certificate holder's operations specifications; or

  (2) Parts 91 and 97 of this chapter, if the certificate holder's
  operations specifications do not specify takeoff minimums for the
  airport.

  §91.175 Takeoff and landing under IFR.

  ...

  (f) Civil airport takeoff minimums. This paragraph applies to persons
  operating an aircraft under part 121, 125, 129, or 135 of this
  chapter.

  (1) Unless otherwise authorized by the FAA, no pilot may takeoff from
  a civil airport under IFR unless the weather conditions at time of
  takeoff are at or above the weather minimums for IFR takeoff
  prescribed for that airport under part 97 of this chapter.

  (2) If takeoff weather minimums are not prescribed under part 97 of
  this chapter for a particular airport, the following weather minimums
  apply to takeoffs under IFR:

  (i) For aircraft, other than helicopters, having two engines or less—1
  statute mile visibility.

  (ii) For aircraft having more than two engines—1⁄2 statute mile
  visibility.

  (iii) For helicopters—1⁄2 statute mile visibility.

  C056, IFR Takeoff Minimums, Part 121 Airplane Operations - All
  Airports.

  a. Standard takeoff minimums are defined as 1 statute mile visibility
  or RVR 5000 for airplanes having 2 engines or less and ½ statute mile
  visibility or RVR 2400 for airplanes having more than 2 engines.

  b. RVR reports, when available for a particular runway, shall be used
  for all takeoff operations on that runway. All takeoff operations,
  based on RVR, must use RVR reports from the locations along the runway
  specified in this paragraph.

  c. When a takeoff minimum is not published, the certificate holder may
  use the applicable standard takeoff minimum and any lower than
  standard takeoff minimums authorized by these operations
  specifications. When standard takeoff minimums or greater are used,
  the Touchdown Zone RVR report, if available, is controlling.

  d. When a published takeoff minimum is greater than the applicable
  standard takeoff minimum and an alternate procedure (such as a minimum
  climb gradient compatible with aircraft capabilities) is not
  prescribed, the certificate holder shall not use a takeoff minimum
  lower than the published minimum. The Touchdown Zone RVR report, if
  available, is controlling.

  C078, IFR Lower Than Standard Takeoff Minimums, 14 CFR Part 121 Airplane Operations - All Airports.

  Standard takeoff minimums are authorized in operations specification
  paragraph C056. The certificate holder is authorized to use lower than
  standard takeoff minimums in accordance with the limitations and
  provisions of this operations specification as follows.

  a. Runway visual range (RVR) reports, when available for a particular
  runway, shall be used for all takeoff operations on that runway. All
  takeoff operations, based on RVR, must use RVR reports from the
  locations along the runway specified in this paragraph.

  b. When takeoff minimums are equal to or less than the applicable
  standard takeoff minimum, the certificate holder is authorized to use
  the lower than standard takeoff minimums described below:

  (1) Visibility or runway visual value (RVV) ¼ statute mile or
  touchdown zone RVR 1600, provided at least one of the following visual
  aids is available. The touchdown zone RVR report, if available, is
  controlling. The mid RVR report may be substituted for the touchdown
  zone RVR report if the touchdown zone RVR report is not available.

  (a) Operative high intensity runway lights (HIRL).

  (b) Operative runway centerline lights (CL).

  (c) Serviceable runway centerline marking (RCLM).

  (d) In circumstances when none of the above visual aids are available,
  visibility or RVV ¼ statute mile may still be used, provided other
  runway markings or runway lighting provide pilots with adequate visual
  reference to continuously identify the takeoff surface and maintain
  directional control throughout the takeoff run.

  [NOTE: If an operator is not authorized RVR 1000 the POI will not
  select RVR 1000 in the OPSS. If the OPSS is not available the POI
  should delete subparagraph b(2), b(3), & b(4) from the word
  boilerplate.]

  (2) Touchdown zone RVR 1000 (beginning of takeoff run) and rollout RVR
  1000, provided all of the following visual aids and RVR equipment are
  available.

  (a) Operative runway centerline lights (CL).

  (b) Two operative RVR reporting systems serving the runway to be used,
  both of which are required and controlling. A mid-RVR report may be
  substituted for either a touchdown zone RVR report if a touchdown zone
  report is not available or a rollout RVR report if a rollout RVR
  report is not available.

  [NOTE: If an operator is not authorized RVR 500 the POI will not
  select RVR 500 in the OPSS. If the OPSS is not available the POI
  should delete subparagraph b(3), & b(4) from the word boilerplate.]

  (3) Touchdown zone RVR 500 (beginning of takeoff run), mid RVR 500,
  and rollout RVR 500, provided all of the following visual aids and RVR
  equipment are available.

  (a) Operative runway centerline lights (CL).

  (b) Runway centerline markings (RCLM).

  (c) Operative touchdown zone and rollout RVR reporting systems serving
  the runway to be used, both of which are controlling, or three RVR
  reporting systems serving the runway to be used, all of which are
  controlling. However, if one of the three RVR reporting systems has
  failed, a takeoff is authorized, provided the remaining two RVR values
  are at or above the appropriate takeoff minimum as listed in this
  subparagraph.

  (4) At foreign airports which have runway lighting systems equivalent
  to U.S. standards, takeoff is authorized with a reported touchdown
  zone RVR of 150 meters, mid RVR of 150 meters, and rollout RVR of 150
  meters. At those airports where it has been determined that the runway
  lighting system is not equivalent to U.S. standards, the minimums in
  subparagraphs a(1) or (2), as appropriate, apply.

  c. Takeoff Guidance System, If Applicable. If the certificate holder
  is authorized to use takeoff minimums based upon the use of takeoff
  guidance systems, the minimums will be specified for the aircraft
  listed in the Table 1 below. The certificate holder shall conduct no
  other takeoffs using these takeoff minimums. If subparagraph c is not
  authorized, N/A will be annotated in each of the columns in the table.

  (1) Special provisions and limitations.

  (a) Operative high intensity runway lights (HIRL).

  (b) Operative runway centerline lights (CL).

  (c) Serviceable runway centerline markings (RCLM).

  (d) Front course guidance from the localizer must be available and
  used (if applicable to guidance systems used).

  (e) The reported crosswind component shall not exceed 10 knots.

  (f) Operative touchdown zone, and rollout RVR reporting systems
  serving the runway to be used, both of which are controlling, or three
  RVR reporting systems serving the runway to be used, all of which are
  controlling. However, if one of the three RVR reporting systems has
  failed, a takeoff is authorized, provided the remaining two RVR values
  are at or above the appropriate takeoff minimum as listed in this
  subparagraph.

  (g) The pilot-in-command and the second-in-command have completed the
  certificate holders approved training program for these operations.

  (h) All operations using these minimums shall be conducted to runways
  which provide direct access to taxi routings which are equipped with
  operative taxiway centerline lighting which meets U.S. or ICAO
  criteria for CAT III operations; or other taxiway guidance systems
  approved for these operations.

  (2) The certificate holder is authorized to use the following takeoff
  minimums for the airplanes listed below.

  Table 1 (N/A = Not Authorized) Airplane M/M/S Lowest Authorized RVR
  Required Takeoff Guidance System

  [NOTE: If an operator is not authorized pilot assessment the POI will
  not select this statement in the OPSS. If the OPSS is not available
  the POI should delete subparagraph d in its entirety from the word
  boilerplate.]

  d. Pilot Assessment of RVR for Takeoff (if applicable). In
  circumstances when the touchdown zone RVR reporting system has failed,
  is inaccurate, or is not available, the certificate holder is
  authorized to substitute pilot assessment of equivalent RVR for any
  touchdown zone RVR report required by this operations specification
  paragraph provided that:

  (1) The pilot has completed the FAA-approved training program for
  visibility assessment in lieu of RVR, and

  (2) Runway markings or runway lighting is available to provide
  adequate visual reference for the assessment.


Are there any examples of sustained human-powered flight above ground effect?

The FAI's photo of Daedalus shows its height above the sea to be considerably more than its wingspan, putting it out of ground effect.
(Wikipedia says that most of the flight was 15 to 30 feet high, well within ground effect because the wingspan was 112 feet.)

I couldn't find any official FAI record for height achieved by a human-powered aircraft, though.


When to turn from crosswind to downwind to base in a circuit?

Like almost everything (aviation or otherwise), this is just something you learn with practice!

I was taught to turn downwind to base when the threshold was between 4 & 5 o'clock (in a RH circuit).

Here's a good graphical representation in a LH circuit.

]

  At the end of your downwind leg, when you once again reach a 45° angle to the runway, do a medium 30° turn onto base.

(Image & Text source: http://www.ppl-flight-training.com/circuits-briefing.html)

As for the base leg being high or low - it shouldn't be a problem. You can easily correct this.

Too high:reduce power 50-100rpm, lower the nose slightly to maintain speed
Too low: Increase the power slightly.

As was commented, it is also worth considering the wind direction before you depart. On a perfect day, the wind will be directly down the runway towards you on final. Consider the effect of this on your circuit? I find it useful to draw the circuit, and an arrow with the wind direction. Then consider when to turn early/late as appropriate.

Finally remember the GOLDEN rule: You can ALWAYS go around. (Assuming you have a fan up front!)


How to find flying directions (similar to driving directions) for navigation?

The traditional (i.e., "old") method is to spread out aviation charts on a large table, and use a plotter to hand-craft a flight plan on paper. Victor airways (the VOR airway network) are depicted both on VFR sectionals and on IFR low & high altitude enroute charts. The pilot/navigator will mark his or her origin and destination, and eyeball the available airways to come up with a suitable route, much like a driver would use a national atlas to find what interstates/highways to take for a long road trip. These maps depict all the information needed about distances, courses, minimum altitudes and airspace classifications.

Planning by hand may also involve the use of the Airport/Facility Directory (A/FD), which has information about airports, and the Terminal Procedures Publication which shows what instrument approaches are available at each airport and any necessary IFR departure procedures, takeoff weather minimums, etc.

Nowadays, people will more often use computer planning tools like AOPA Flight Planner, fltplan.com, etc. There are a large number of sites and software programs for this, some free, some requiring paid subscription / purchase. Most recently, mobile apps for smartphones and tablets have emerged with the same capabilities.

The best such sites/software will also provide the necessary information about terrain, takeoff minimums, departure procedures and so on, and even give you current NOTAMs, weather forecasts, etc. Many also have aircraft performance databases (or allow you to create one yourself for your airplane) and can do performance calculations for you. Some will even find the cheapest places along your route to purchase fuel, and also give you information about local transportation and accomodations.

Note, though, that neither the FAA nor any other civil aviation authority authorizes the pilot to rely on software resources. The pilot is still always responsible for verifying that he or she has complete, accurate information from official sources. In other words, if you're using software to plan your flight, and you violate restricted airspace that your flight planning software didn't warn you about, you'll be held responsible for not verifying the information and catching the error. So be careful what you use and rely on!


I won't be displaying mathematics or even a guesstimate here because this subject is somewhat beyond my scope of competency. However:

To shoot something into orbit with a catapult from ground level is not feasible, as the object would immediately burn to ashes, no matter what the material would be. The required velocity to reach orbit is about 40 000km/h, and to make things worse, you'd have to reach that speed at basically zero altitude, with a very dense atmosphere creating friction.

See this question and answers from physics stack exchange for further information.


What are the differences between a VOR and a VORTAC?

VOR stands for VHF Omnidirectional Range. It is a navigation beacon intended  for civil use and provides a user with a radial to/from the station. It works on frequencies between 108.00 and 117.95 MHz.

VOR/DME station PEK (Beijing):

source: Wikimedia, author: Yaoleilei

TACAN stands for TACtical Air Navigation, a military system that is similar to VOR but with higher accuracy. It works on frequencies between 960 and 1215 MHz.
Part of the TACAN is DME (Distance Measurement Equipment), which works in the same frequency band. The DME used in TACAN is the same that can be used by civil aircraft. Due to the higher frequency the system is more accurate and the antenna is much smaller and therefor easier to deploy (e.g. on a ship, on a battlefield).

 (source: wikimedia, US Air Force, Camera Operator: SENIOR AIRMAN JONNA N. WILSON)

A VORTAC combines the VOR and TACAN in one location. Civil users will use the VOR signals which have the same performance as ordinary VOR signals. In addition they use the DME from the TACAN. Effectively a VORTAC is like a VOR/DME.
Military users only use the TACAN, for them a VORTAC is the same as a TACAN.

source:Wikimedia, author: Hans-Peter Scholz Ulenspiegel


When might an aerodrome contain a public right of way?

Less busy than Gibraltar, but in the UK proper, Sumburgh in Shetland is an example of "road crossing the runway" on a relatively active airport - it even comes complete with level crossing gates, which are a startling thing to see on the road ahead when you know there's no railway!


Who pilots an aircraft that is on a delivery flight?

Typically the customer will travel to the manufacturers location for a final inspection and acceptance of the new aircraft. This includes one or several test flights with staff of both the manufacturer and the customer on board, thorough systems checking and final modifications if necessary. The acceptance of the aircraft is then made official by signing off a pack of papers.

Then the customer transfers the final sum of money to the manufacturer and the aircraft is signed over to the customer. The delivery flight is typically operated solely by the customer's staff, however if it is the first aircraft of the specific type for the customer, the manufacturer may send training staff along for final training of the ground staff at the customers location if agreed so.


What are good study guides/practice tests for the airframe maintenance certificate?

I used the Dale Crane series of study guides from ASA years ago, available from either of those two links as well as many other places.

Here is the specific study guide for Airframe, but you will also want the General study guide. These are for written test prep, but might also include Oral and Practical (O&P) test prep.

Image from mypilotstore.com product listing

There are also other options out there. Gleim offers an AMT test prep course, as does ASA in their AMT Prepware, but I don't know that I have any experience with either one. I definitely used one of the digital test prep packages out there, but I can't remember which one. I do like the digital tests, especially since that is probably how you will be taking the writtens anyway.

I also studied the Jeppesen textbooks in addition to the FAA textbooks you mentioned.

You will also want to study the Practical Test Standards (PTS) for your O&P test prep.


What are those bumps on top of the Antonov-225?

According to the Airliners.net forum, they are fairings that cover hardpoints used for attaching outsize loads.

  Outsize loads that cannot fit into the capacious cabin (including Buran and Energiya components) are carried 'piggyback', the load supported on two main attachments above the center section. These supports and other smaller ones along the fuselage top are faired over when not in use.

The text is quoted from aeronautics.ru (web archive link).

Please note that the two large ones were not used for carrying the Buran space shuttle, as shown in the photo posted below. (More pictures here.)


Why in certain airports the windows are blocked while others not?

Keep the sun out if facing south or west, help keep the temperature down.


Did Air Europe fly to Toronto from Lamezia Terme?

The Wikipedia page you checked is for the British Air Europe. The Italian airline of the same name operated 12 Boeing 767's in the 90's.

The image below shows the Italian airline at Toronto in the mid-90's.

(airliners.net)

The 767-300ER shown above is capable of reaching the West Coast of the US from Italy.

(gcmap.com) The Boeing 767-300ER has a range of 5,980 NM.


What could reasonably be done in case 7,500 airplanes must be landed quickly?

There's roundabout 400 paved runways over 2438 m (8000 ft) in the USA and EU, respectively, and about 200 or so in China and Russia, respectively, so that's about 1200. They are long enough to deal with most aircraft. Some might be untowered or unavailable, but then there are other countries, too. Estimates for "commercial" airports worldwide run around 4000 (there are about 9000 IATA codes, apparently).

So, every suitable runway would have to accommodate around 2 to 10 aircraft.

You can have around 50 to 70 movements per runway per hour, though you need separation of up to 3 minutes to avoid wake turbulence if a smaller jet arrives after a heavy. Let's say 30 landings per hour, and we're talking about 20 minutes, just in terms of pure runway capacity.

Now, to get all those planes lined up nicely... Parking might get crowded, too, but I'd think it would be doable - just fill up taxi ways progressively (presumably you don't care about take-offs for a while). See this diagram of aircraft parking prior to the Tenerife disaster (where many planes diverted to the small Tenerife airport due to a bomb in Las Palmas).

At any rate, the practicalities would be daunting. Would be interesting to see a proper feasibility study.


How realistic is atc-sim.com as an ATC simulator?

Not very realistic.

it's text-based; no readbacks.
there are no approach clearances. You can assign speed, altitudes, and headings, but there is no way to instruct an aircraft to execute a specific approach.
there aren't, really, any missed approaches or go arounds
no emergencies

Basically, it' just a game of "keep the aircraft separated", but it doesn't properly simulate how ATC works.


Are planes assigned different climb angles from the airport by the tower?

There can be many reasons. Flights taking off one after another:

have different destinations
have different weight and balance
have difference in wings and wingtips
have pilots with difference in skills
got different takeoff directions by ATC
are trying to avoid wake turbulence

Off all the reasons I mentioned above, perhaps wake turbulence might be playing more role about difference in takeoff angle. There are a ton of questions about wake turbulence, which is worth a read.


How do aircraft window size compare to each other? What are some possible improvements on them?

How aircraft windows compare:

  Aircraft windows can be made bigger by improving the materials of the window or fuselage or reducing the amount of Gs the window frames get by changing the exterior shape and design of the fuselage. Another way is making the window surfaces smoother (to reduce surface friction) or changing the shape of the window itself.


What do I request when contacting tower of an airspace I'm transiting over?

This will vary for every airspace so lets go over them in descending order.
Class B (Bravo): First off, keep in mind for your future solos that as a student pilot you are not allowed to fly solo in class B airspace unless your instructor has given you training and a logbook endorsement for that specific class B (see 14 CFR 61.95). But if your instructor is in the plane then technically they are accepting the clearance, not you. For Bravo airspace a clearance is explicitly required and a typical exchange will go something like this:

PIC: "1234XY 5 miles south west of KPHL at 4000 heading to KPNE requesting transition through the airspace."
ATC: "1234XY squak 3425 and ident, altimeter 29.92"
PIC: "1234xy 3425 29.92"
ATC: "Ident received, you are cleared through to KPNE on your current heading at 4000"

En route you may get traffic advisories or other instructions while in the space so you need to stay on the frequency.
Class C (Charlie): For Charlie airspace you only need to establish 2-way radio communication. A response containing your call sign will allow you into the space. Lets look at an example

PIC: "Allentown approach 1234XY 20 miles to the southeast of Queen City at 3000 in bound for landing at Queen City"
ATC: "1234XY standby"

Anytime you hear your call sign, it is considered to be the establishment of 2-way radio communication, if you hear "aircraft calling Allentown, standby", you have not established 2-way communication and must remain out of the space since they did not respond with your call sign. Likewise you may be explicitly instructed that you must remain out of the space.
Class D (Delta): Delta airspace typically  extends up to 2500AGL, and you can often climb over it flying VFR. You do not need to hail the tower when doing so but many people do so out of courtesy. If you intend to enter Class D, follow the same procedure as Class C.
You can find the whole breakdown here
Flight Following: Where available and workload permitting you may be able to pick up flight following while in route. You can also coordinate a hand off from them to the airspace you are entering.


The different airspeeds:

IAS is indicated airpseed
CAS is calibrated airspeed
EAS is equivalent airspeed
TAS is true airspeed

CAS is IAS corrected for instrumentation and position errors. The errors are most pronounced in slow and high angle-of-attack flight.

IAS figures in aircraft manuals are actually converted from CAS. For ease of use.

How CAS is determined (Wikipedia link).

However, a modern plane with an air data computer (ADC) actually displays CAS, despite being labelled as IAS.

Below 200 knots and 10,000 feet, for all purposes, CAS equals EAS.

As the plane goes faster and higher and compresses the air, the air changes density, an effect known as compressibility that affects the CAS reading.

EAS is computed by the ADC on a modern fast plane, and together with the density altitude, the TAS is then known.

Ground speed and track (from GPS, navaids, and/or INS) together with the TAS allows the FMS to calculate and display the wind speed/direction.

Before ADC's, pilots used charts like those in the answer.

Summary:

In a modern plane, what the pilot actually uses is CAS, despite being labelled IAS. And EAS is used in computing the TAS by the ADC.

For engineers, TAS (actual velocity through the air) is used in lift equations, EAS is used in calculating dynamic pressures on the plane (TAS corrected for air density).

Source used and a must read: Aerospaceweb.org—Types of Airspeed


What happens if you do emergency landing on a US base in middle of the ocean?

Wake Island has had aircraft divert there before, as it serves as an ETOPS diversion airport.

Per the remarks on AirNav and the NOTAMs:

  RSTD: VERY LIMITED OPERATIONS STATUS, AVBL FOR EMERG LDG AND MIN PRIORITY TFC.

  TRAN ALERT: SVCG FEES RQD. TRAN SVC HRS 2000-0400Z (0800L-1600L) TUE-SAT. CLSD SUN, MON, HOL.

  FUEL: FLIGHT CREW REQUIRED TO ASSIST IN REFUELING. J5(MIL). FLUID - W, SP, PRESAIR.

It's possible you could plan to fly through there with prior permission, as with most military fields. AirNav reports 2% of the average of 49 operations per day are transient general aviation, so it's not entirely military, but government and contractors probably make up most of this.

If your emergency is just that you forgot to have enough fuel, you should be able to get more fuel and depart again, for a fee. If there is a fuel leak or some other maintenance issue, you could be in for a longer stay.

  RSTD: NO AIRCRAFT MAINTENANCE AVBL.

As with the airliner that diverted, maintenance equipment and personnel will have to be flown in for any work that needs to be done.

You should be in contact with Oakland ARTCC through San Francisco ARINC in the oceanic airspace, and can call base operations ahead of time to advise of your needs. If it's outside of their normal staffing hours, they need at least 30 minutes notice to open back up.


How do airlines provide crews for the return leg of a long-haul flight?

You presume that they flew back the very same day... but that is an incorrect presumption.

For long flights over about 8 hours, strict rest limits apply so they cannot fly again for 8-10 hours at a bare minimum. Typically, a crew from a long-haul flight will stay in a hotel in the destination city for anywhere from 12 to 48 hours, depending on the flight length, timezone changes, airline schedules, union contracts, and so on. Yes the hotels and travel bonuses costs the airline a pretty penny but that's the cost of doing business.

So at this very moment there will be 1 or maybe 2 LX crews, resting (or touristing...) in San Francisco, waiting to fly a return service.

For more information you can google or ask a new question on Fatigue Risk Management Systems.


One of the most important goals of standard phraseology in radio communications is to ensure that words are distinct enough that a momentary garble doesn't ruin understanding of the transmission. (This is also why a phonetic alphabet is used -- Alpha, Sierra, Foxtrot, etc., rather than just saying the letters A, S, F, ... Imagine if ATC told you on voice something like "taxi to runway 7 via S, hold short F4" and now instead make it "taxi to runway 7 via Sierra, hold short Foxtrot four". Which is less likely to be misinterpreted?)

Another goal, of course, is to have a limited vocabulary of distinct terms that can be used to state things between people who may not be all that familiar with the language.

As you correctly note, "ascend" and "descend" sound very similar. If you for whatever reason miss out on the first syllable, they're outright identical! I'd call it a Bad Thing (tm) to have a single syllable potentially making the difference between just another day at the office, and a mid-air collision.

So when faced with the choice of whether to say "climb" or "ascend", in light of the fact that we're already using the term "descend", it makes sense to use a clearly distinct term for the opposite case to clearly differentiate the two. Hence "climb". The same argument can be applied to the case of both terms being selected together, without either having been selected before the other.

As an aside, "maintain" is also clearly distinct from both, further reducing the risk of confusion. If your altimeter reads 5,000 ft and are asked to "climb to 4,000 feet" or "maintain 6,500 feet" (as opposed to climb and maintain), then you know that someone needs a reality check, and can ask for clarification, even if that request for clarification is only along the lines of "say again assigned altitude and QNH".


quadcopters — should the propellers/motors all be at the same height

Tandem rotor helicopters have the aft rotor elevated to keep it clear of the front rotor's downwash and improve performance in forward flight (at the cost of reduced performance in rearward flight).

Most small quadcopters achieve substantial pitch angles in forward flight, often in excess of 30 degrees, which keeps the aft rotors out of the downwash anyway. Therefore, your proposal changes nothing in hover and fast forward flight, improves performance somewhat in slow forward flight and reduces performance in rearward flight.


Is there a crosswind that would perfectly cancel out the "torque" of a C172 on takeoff?

It is reasonable to believe, (as it is with most hypothetical questions of this sort...) that the answer is yes.  However, there are a few things to consider:

It would need to vary to the degree that the throttle is advanced.

It would need to vary during the acceleration as aerodynamic effects change.

So, if you think you might be able to listen to ATIS and discern that you won't need rudder on the takeoff roll, it isn't that simple.


How did the long loop of tape in a magnetic cockpit voice recorder work?

Most looped tape mechanisms are a variation of this:

(this is an 8-track audio cassette)

The tape is pulled from the center of the spool, and fed back to the outside of the spool.

Some CVRs use two spools and autoreverse instead.

On the right, an example of a flight data recorder. (on the left, the digital storage of a modern FDR).


Never heard of any sort of takeoff speed "category" applied to operators in US rules, but we do have rules (in an airline's OpSpecs) for our aircraft that tell us at what min visibility centerline lights are required for takeoff (and landing as well).

If an airport were considering investing in Centerline Lights, that recommendation, combined with a little research into the requirements of the airlines who'd potentially operate into & out of that runway, would provide a basis to determine what incremental gain in utilization the runway could have. (Along with some meterology hisoric data -- numbers of hours/days at or below a given RVR value.)

The term very high take-off speed does seem a little nebulous; airliners' takeoff speeds are pretty high compared with most General Aviation aircraft, and unless you're building a runway for fighter or experimental jets, there aren't that many aircraft with higher takeoff speeds than we have that it would seem worthwhile to install CL just for them.

But, who knows... Maybe another ICAO document does define that term somewhere.


What is the purpose of several mandatory stops (RWY AHEAD) at busy airports?

A full stop at a red sign is only mandatory if ATC has not given you explicit clearance to proceed further. Aircraft will be instructed to "hold short" of the runway, and these signs indicate where the aircraft should stop.

The CAT II/III signs are only for holding when CAT II/III operations are active on that runway. This refers to categories of the Instrument Landing System (ILS) that are currently in use. An aircraft only needs to stop at the sign applicable for the current conditions, as instructed by ATC. Generally if an aircraft must stop at the CAT III holding point, they will later be cleared either to take off or line up and wait on the runway. That clearance means they do not need to also stop at the CAT I point.

On page 47 of this ICAO Aerodrome Standards manual there is a table showing the required distances from runway center line for holding positions. For example, a long runway (code 4) would require 75 m normal distance, and 90 m for CAT I/II/III approaches. These numbers increase with runway altitudes over 700 m (2,300 ft) elevation. There are also many other factors in the airport configuration that might require a greater distance.

The different holding points are to ensure that in lower visibility conditions, there is more room for added safety. It also helps to ensure that holding aircraft do not interfere with the precision approach signals. The CAT III holding point is further from the runway to ensure that the guidance equipment will provide CAT III accuracy and avoid interference from aircraft and vehicles. If there is not a clear procedure in effect to keep these areas clear, interference can happen, and the faulty signals can result in the airplane following an incorrect path.


Can you re-register a de-registered aircraft with the same N-number?

The FAA has a page that sort-of takes you through this process.  Basically it boils down to this:

If your registration has expired you still have ~90 days to register the aircraft

  If a renewal application was first received by the Registry after the expiration date, the renewal process no longer applies. An aircraft owner may apply for registration of an unregistered aircraft under 14 C.F.R. §4731(a), by filing an Aircraft Registration Application, AC Form 8050-1, the $5.00 registration fee, and evidence of ownership (if it is not already on file at the Registry).

So it's a "new registration", but you can keep your N number. (Yes, you have to use an official, FAA-Provided 8050-1 form - you can't download them anymore. You're also going to want to talk to someone at the Aircraft Registration Branch or your local FSDO before you start filling out forms because you don't want your form to show up after the 90 day window or you wind up in the other category...)

After about 90 days your N number is Cancelled & unavailable for 5 years

  When an aircraft registration is not renewed, the cancellation of the N-number assigned to that aircraft will take place approximately 90 days after the expiration of an aircraft's registration. Upon cancellation, an N-number will be unavailable for re-assignment or reservation for a period of five years.

At this point you have to talk the aircraft registration branch, but my understanding is you are out of luck -- That N number is void and a new number will be issued when you register the aircraft (at which point you must apply the new N number to the aircraft in accordance with FAR 45, which typically means repainting at least part of the tail).
You must get a new airworthiness certificate bearing the new registration number from your local FSDO.

In both of these cases your airworthiness certificate is invalid* (because without a valid registration you have no authority to operate the aircraft).

In the first case you will not need a replacement airworthiness certificate (because your N number hasn't changed), but if your N number has been cancelled you will  need a new airworthiness certificate issued with the new N number on it.

Total time for all the paperwork to be processed depends on which bucket you fall into -- the aircraft registration branch usually has about a 30-day backlog (check here), plus time for the post office to move the paper from point A to point B, so a lag of a little over 30 days is what you should expect.
If a replacement airworthiness certificate is required that will probably add a few days to the process as well.


What are these markings on the A380 wing?

The darker areas denote where it is safe to step. Stepping outside of these areas could cause damage to the aircraft.

Here's a closeup of the warning:

(This happens to be a photo of Qantas Flight 32 after its un-contained engine failure)


How are disabled passengers evacuated during emergency?

You can find the full text of the FAA's recommendations in this AC

But the flight attendant is responsible for discussing with them whats best.

  ASSISTING DISABLED PERSONS. The handicapped person knows best . the
  manner in wbch he can be assisted, and flight attendants should not
  hesitate to discuss this with the individual. Keep in mind that
  different disabilities have different needs, and injury can result if
  a person with a disability is improperly assisted.

The AC goes on to describe most major scenarios and common instances.


Can I accept a SID if I can't make the required climb gradient on a single engine but have no problem on two engines?

Depending on certain factors, you can accept a SID clearance knowing that you cannot make the required climb gradient with one engine inoperative (OEI).

The FAA Aeronautical Information Manual (AIM) 5-2-8 ODP and SIDs states this:

  ODPs and SIDs assume normal aircraft performance, and that all engines are operating (AEO).  Development of contingency procedures, required to cover the case of an engine failure or other emergency in flight that may occur after liftoff, is the responsibility of the operator.

This answer begs another question and what are some contingency procedures you can consider when accepting a SID when the required climb gradient is not possible with OEI procedures?

The FAA lists two possible places for this information:

AC 120-91 - Airport Obstacle Analysis
Instrument Procedures Handbook (FAA-H-8261-1) Chapter 1.

AC 120-91 talks about how runway analysis is used to comply with Part 121 / 135 obstacle climb requirement.

Instrument Procedures Handbook provides additional information on how OEI takeoff obstacle clearance requirements are different than TERPS requirements.  Besides using runway analysis, there isn't a lot of additional information on contingency procedures.

Here are my contingency procedures in the preferred order

Runway Analysis - Let an engineer figure out the maximum weight to takeoff and be able to climb above the obstacles
Radar vectors - Once ATC issues the words "Turn left / right heading xxx°" they are equally responsible for terrain clearance
See and avoid the terrain (VMC only) - If we can see the obstacles... hopefully we can miss them.  Of course, mountains don't care if you can see them or not.  They don't move.
Obstacle Departure Procedures (ODP) using OEI calculations.
SID using OEI calculations.

It would be great if others come up with a different set.  I would love to see them.   I will typically work through this listing and if I am taking off from an airport without radar services in IMC where I do not have runway analysis, I need to be able to make the ODP or the SID on OEI performance.


How does a helicopter pilot execute an auto-rotation landing?

I am going to assume that by "critical", you mean survivable.  I will also assume that the engine failure occurs at a height which will kill you.
It's not so much critical steps, it's critical outcomes.  The single most critical outcome is to preserve, or regain, rotor RPM.  What steps are needed to do this will depend on what the aircraft is doing when the engine quits and, to a lesser extent, the type of the helicopter.  I will generalise for an "average" helicopter in straight and level flight.
The immediate action that is drilled into everyone from the very earliest hours as a student is to lower the collective.  Doing this has three effects.  It removes the positive pitch from the blades which removes most of the drag, it aligns the rotor thrust vector with the axis of rotor rotation therefore not using rotor energy for anything except lift and it causes a clutch to disengage the rotor from the engine allowing it to freewheel.  From this point onwards, you are heading back towards earth.
The second immediate action at the same time as lowering the collective (assuming forward flight) is to pull back on the cyclic to flare.  This loads the disc which causes it to "cone" upwards which reduces the disc diameter.  Therefore, the centre of gravity of the disc moves inwards and due to conservation of angular momentum, the rotor RPM increases.  For quite complex reasons, the nose of the helicopter will also pitch down when the collective is lowered so pulling back counters that tendency.
The third immediate action is to push in the pedal on the opposite side to the rotation of the blades. If the blades rotate counter clockwise (to the left as the pilot sees it) you push in right pedal to reduce the thrust which is produced by the tail rotor which is no longer countering the yaw caused by the drag from the powered rotor.  This is less critical than the first two and although it can be dangerous and get you into an uncomfortable attitude, it is usually possible to recover from not pushing the pedal in immediately.  If you've got rotor RPM, then you can sort it out.
Now you have successfully entered autorotation.  From here, fly more or less normally to the next critical point which is about 50' off the ground.
What you've done is to ensure that the rotor has flying RPM and that you are managing energy by trading potential energy (height) for kinetic energy (rotor RPM).  The conversion is done by the airflow which now comes from under the disc and "drives" the rotor to maintain RPM.  The pitch is neutral, or maybe even negative but, the relative airflow is now upwards through the disc and therefore, the blades have a positive angle of attack and generate some lift.  This stops the helicopter from falling.  There is some drag generated as a consequence of generating that lift, but it is easily overcome by the power which is now driving the rotor from that upward airflow.
As long as you are descending, that conversion will happen and your RPM will be maintained.  The controls are rigged such that with the collective fully down, RPM will remain in the normal range.  Sometimes you have to tweak it a little with small amounts of collective, flares and turns but in general, you just fly towards your landing spot.  The allowed RPM range is greater in autorotation.  For example (and from memory), the R22 has a range of 97-103% in normal flight and 90-110% in autorotation.
You are now descending with a high rate of descent and usually, significant forward speed.  You need to reduce both of those to get to a safe arrival. To do this, there are three more critical steps.
Starting at about 50 feet (depending on lots of factors but let's stick with the average helicopter which entered autorotation from straight and level with significant altitude), you flare the aircraft by pulling back on the cyclic.  This will immediately begin to slow the aircraft.  It will also begin to increase RPM (you are now converting speed into rotor kinetic energy).
At the same time, you increase collective to reduce the rate of descent by increasing the lift generated.  This will rapidly increase the drag, but now the energy needed to maintain the RPM is coming from the flare which is converting speed into RPM.  You also need to put in pedal to stop the aircraft from yawing as the drag increases on the rotor.
Providing you get the entry right and your flare reduces the speed and rate of descent to something survivable, then you will walk away.  You might wreck the helicopter and break some bones, but arrive at 10 feet with only 20 knots and 150 feet per minute rate and you'll get away with it.
If you are well trained and in practice, then you will land safely and smoothly with no damage to  machine or people.
In summary, critical steps:

Entry.  Lever down, cyclic back, pedal in.
Arrival.  Cyclic back, lever up, pedal in.


Should depressurization be considered in the event of an inflight cabin fire?

Some aircraft do have a manual decompression button which can be used by the pilot in a situation like this.  Keep in mind however that it will only help until the pilot descends (which you will want to do asap in order to land) and the air isn't as thin.

It is very important for the crew to get on the ground as rapidly as possible, and simultaneously attempt to put out the fire in order to minimize the amount of damage that can be done.  The single biggest factor in an aircraft fire is how much time elapses before they land and can evacuate.

Also, if the cabin depressurizes, typically the oxygen masks deploy automatically which when combined with a fire can have even more disastourous results.


What is the total pressure of an air stream in motion?

The total pressure assumes that the is an isentropic evolution from air in movement up to an static state. The total pressure is the pressure at such state.

The way to compute this "made up" variable you need to compute the static pressure and the dynamic pressure (driven by the air speed).

So the answer is:

the sum of the dynamic and static pressure

But remind that is not "a real property" but more a way to measure the maximum pressure that can be achieved from a fluid in movement without adding extra energy.


Where is the official definition of pressure altitude?

Pressure Altitude

As defined by FAA in the Pilot's Handbook of Aeronautical Knowledge:

  Pressure altitude is the height above a standard datum plane (SDP),
  which is a theoretical level where the weight of the atmosphere is
  29.92 "Hg (1,013.2 mb) as measured by a  barometer. An altimeter is essentially a sensitive barometer calibrated to indicate altitude in
  the standard atmosphere. If the altimeter is set for 29.92 "Hg SDP,
  the altitude indicated is the pressure altitude. As atmospheric
  pressure changes, the  SDP may be below, at, or above sea level.
  Pressure altitude is important as a basis for determining airplane
  performance, as well as for assigning flight levels to airplanes
  operating at or above 18,000 feet.

  The pressure altitude can be determined by either of two  methods:
  1. Setting the barometric scale of the altimeter to 29.92 and reading the indicated altitude.
  2. Applying a correction factor to the indicated altitude according to the reported altimeter setting.

More info from the FAA here.

From Docket No. 18334, 54 FR 34304, Aug. 18, 1989, as amended by Amdt. 91-314, 75 FR 30193, May 28, 2010

  §91.217 Data correspondence between automatically reported pressure altitude data and the pilot's altitude reference.

  (a) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder—

  (1) When deactivation of that equipment is directed by ATC;

  (2) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

  (3) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.

  (b) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder or with ADS-B Out equipment unless the pressure altitude reported for ADS-B Out and Mode C/S is derived from the same source for aircraft equipped with both a transponder and ADS-B Out.

ICAO has described how they calculate Pressure Altitude

Source

In relation to QNE:

  When the ISA mean sea level standard pressure of 1013.2 hPa is set on
  an aircraft altimeter subscale, the height so indicated upon landing
  at an airfield is known as the QNE reading. More widely, this is also
  the PRESSURE ALTITUDE, which is alternatively defined as the height of
  any level in the international standard atmosphere (ISA-see above),
  above the level corresponding to a pressure of 1013.2 hPa.

Here is a free tool to calculate standard atmospheric conditions (ISA) at a given geometric or pressure altitude and ambient temperature.


What may cause a strong smell of paint thinner like odor and no power to master in a Piper Warrior?

You've got two unrelated problems: The battery and the smell.

The Battery

Battery electrolyte doesn't really have a "smell" to it - at least not one you're going to notice in the cabin easily. If you open the cell caps on a newly-topped-off flooded battery and sniff you'll get a feeling for what the electrolyte smells like.
If you have a sealed battery you're not going to smell electrolyte unless the battery completely loses its mind and vents a large quantity of electrolyte - you'd definitely notice the mess in the battery box if that happened.  You may notice it in a conventional flooded-cell battery if the battery is overcharged (from high bus voltage, or from trying to charge a flat battery after jump-starting the plane), but again it's not going to be readily apparent in the cabin unless you've lost a large quantity of electrolyte or you're really boiling the battery from an over-charge.

If your battery's cells are full (or it's a sealed battery) and you didn't leave the master switch on then the likely cause of it being flat is that it's old and can't handle the low temperatures of winter anymore (or if it's a new battery it may have developed an internal fault and discharged itself).

If you left the master switch on putting the battery on a charger/conditioner overnight can usually bring it back to good operating condition. You can try that on a flat battery from an unknown cause too: The good charger/conditioners will warn you if they think the battery has an internal fault. If an overnight charge doesn't resolve the issue then you're going to need to replace the battery before further flight (and frankly replacing the battery is cheap insurance against getting stranded somewhere, so it merits consideration anyway).

The Smell

The smell of 100LL changes as it evaporates - lighter aromatic components vaporize faster, and will waft out of the cabin more quickly, leaving the smell from the heavier hydrocarbons lingering.
As you discovered avgas that's been evaporating for a while loses the characteristic benzene/toluene scent we're familiar with from sumping the tanks and has the general odor of turpentine/conventional mineral spirits ("paint thinner").

The first thing to check in the PA28 when you smell something like this in the cabin is the fuel selector valve, as it's a common failure point particularly in cold weather: The packing/tapered plug in the fuel selector valve has shrunk in the cold, and you're leaking fuel around the shaft (which is then soaking into the carpet and evaporating off, giving you the smell in the cabin). Other aircraft may have similar failure modes in their fuel selectors, but I'm a Piper guy so I can really only speak to their systems and associated quirks :-)

Since your shop identified the fuel selector as the problem it's an easy fix: Rebuild or replace the fuel valve and the leak will stop, probably for many years.  (Piper Service Bulletin 355 is relevant to this issue for older Pipers - the O-ring identified in the exploded diagram dries out and shrinks/cracks, allowing avgas to leak around the shaft. There may be something similar in Piper's service documents for the Warrior II, I'm not sure if it uses the same internal valve or not)

Another common failure point would be the O-rings around the primer plunger in aircraft with a mechanical primer (anything before the Warrior III).
This doesn't normally manifest as a lingering smell in the cabin but rather a smell when you operate the primer plunger (usually also accompanied by the plunger being stiff/hard to operate). Much like the fuel selector it tends to manifest when the weather gets cold and things shrink or become brittle, and the cure is to disassemble and appropriately service the plunger mechanism (replace the O-rings and re-lube the mechanism with a fuel-safe lubricant).


Can you guide me about the purpose of fine alignment in inertial navigation systems?

I was a Doppler Radar & INS specialist for the Air Force in the 80s, and learned systems for the F4 (flying brick) and the triple carousel system for the C-5A. These systems used mechanical gyros in combination with accelerometers to establish a "Stable Platform". The carousel idea was state of the art then and rotated 1 revolution per hour to greatly reduce drift.

BATH was used for course alignment, which is an acronym for Best Available True Heading and local gravity to start level. It would then spin up and do fine alignment by sensing Earth rotation to determine True North. Typically this took about 30 minutes. Modern systems us laser gyros which aren't affected by mechanical drift.


In a piston aircraft, how much noise is generated by the engine, and how much by the propeller?

One particular example I can recall is Extra 330. Modification with electric engine have been built (Extra 330LE) keeping the rest of the aircraft quite similar to the original petrol-engine version as far as I know. According to this article electric version was measured to produce 14.5 dB less noise compared to the combustion engine aircraft.

Maybe you can try too look for other combustion engine aircraft converted to electric without making other significant modifications (I am not aware of any other than this Extra 330LE though) as a source for data you are looking for.


How can wingtip vortices affect the direction of the relative wind in front of the leading edge?

Please don't believe everything you read. You healthy scepticism is your best defense against the nonsense you might read about wingtip vortices.

What causes the flow to increase its angle when approaching the leading edge is the low pressure region above the wing. This is not only the main contributor to the wing's lift, but also the reason for the flow pattern ahead of the wing, in combination with the overpressure region around the stagnation point.

Please read this answer and let me know if something is left unclear.


Why do we take off with maximum power settings?

It should come as no surprise that flying an airplane is not like driving a car. When driving a car, you can come to a complete stop and nothing exciting will happen. You cannot do this in an airplane; coming to a complete stop is either the beginning or the end of a great deal of excitement.
Flying near the ground in any circumstance is a hazard. As you say, the goal is to get away from the ground as quickly as possible. This should not be "stress to the engine", engines are designed and maintained to support the full throttle takeoff.


Why is IGN SYSTEM A FAULT dispatch a NO GO on the A320 for ETOPS?

Your assumption is incorrect.

In ELEC EMER CONFIG (see your QRH - ELEC EMER CONFIG SYS REMAINING), Ignition A is the only ignition available and hence that would be your reason why IGN A is needed for EDTO / ETOPS.


Why does a force on a propeller act 90° "ahead" due to gyroscopic precession?

If I say "my brother was born ahead of me", you might reasonably assume that my brother is older than me.  That his birth took place at an earlier point in time.
You seem to be assuming that "ahead" refers to the position that any given blade of the propeller occupied at an earlier point of time.  I.e., a position displaced opposite to the direction that the propeller is rotating.
But if you are driving a car and your passenger says "the light's green, go ahead", would you take that a suggestion to go backwards?  Or to go forwards?
The meaning of "ahead" in the passage quoted in the original question is correct and reasonably unambiguous-- it means forwards along the direction that the propeller is rotating.
Note that the original passage did not contain the word "before".


Cross Country Planning: What do I put in the NavLog for the GPS route?

I can't tell you what specifically to include on your navlog (that's a judgement call you make as a pilot - you determine what has to go on the paper to satisfy yourself that you can complete the flight), but I can give you a crash course in my theory of navigation, and a practical example of how I decide what to put on my navlogs.

What's the point of the Navlog?

At its core a navlog is a list of waypoints such that you could find your way from Point A to Point B via the listed route by using some navigational system.
Ideally the navlog should be usable with at least two independent navigational systems in case one breaks, and for a VFR flight one of those navigational systems should always be "Looking Out The Darn Window!" (the window rarely breaks).

For purposes of this discussion I'm going to focus on waypoint selection and a few other housekeeping tasks. I'm ignoring stuff like calculating headings because while that stuff is important it's also just mechanical math: The waypoint selection requires you to exercise some judgment as a pilot.

A Practical Example: KGON to KMGJ and back.

This is a nice 100 mile flight to use as an example. Let's plot the outbound trip using pilotage and dead reckoning, and the return trip using the GPS. (This is going to get photo-heavy, so I'm burying them in links.)

The first thing you do is draw the straight line between the two airports on the chart. Then follow the line from Point A to Point B and mark off convenient landmarks. I chose Chester Airport, the New Haven railroad/highway/river, abeam the Waterbury-Oxford Airport, the lake & prison north of Danbury (also abeam the Danbury airport), and the Hudson River (you can't miss it!).

  Pilotage Tip: Airports (at least the larger ones) make great landmarks. They're also convenient landing places if you have a problem, so including them as waypoints is a double win.

Almost all of these legs can be completed by pilotage (you can always see the next waypoint/landmark), but one of the legs (Danbury to the Hudson) is about 24 nautical miles and on a hazy summer day you might not be able to see that far. You should therefore be prepared to fly at least this leg by dead reckoning (point the nose in the right general direction based on the heading you calculated, and fly until you see a big river).

The navlog that Skyvector generates for this is somewhat unfriendly-looking, with lots of latitude/longitude fixes in it, and automatically generated ones from Foreflight and similar tools will look about the same. When you write up your navlog you can give each waypoint a descriptive name like I did above so you can remember what you're looking for in case your sectional blows out the window mid-flight.

So that takes care of the outbound trip with visual waypoints - what about the return trip using the GPS?
GPS systems have convenient databases of airports, intersections, and navaids, so we draw the same straight line, then look at the chart and find the waypoints between our two airports that the GPS will know about. The result looks like this and produces a navlog with nice waypoint names.

  GPS Tip: I avoided using Lat/Long fixes in the GPS plan in favor of fixes that you can type in on any GPS, so this is fast and easy to enter on a Garmin 430/530 for example. Newer GPS systems like the touchscreen Garmins let you do "rubber-band flight planning" where you can drag your route of flight around and easily create waypoints wherever you want - you could even set up the same track I did for the outbound flight if you want.

Since you're flying under Visual Flight Rules you're going to want to note down Visual references to go with this navlog (because again if your instructor is anything like mine was your GPS is going to suddenly fail on the return trip while you're merrily following the magenta line).
For this return trip the visual references would be Stewart Airport (and the Hudson River beyond it, even though it doesn't have a dot on this plan), the city of Brewster (which doesn't have a dot, but is identifiable as a city that has power lines, railroad tracks, and a highway immediately east of it), the Danbury airport (KDXR), abeam the Bridgeport airport (at TRUDE), and from there on you can cheat and use the shoreline (even if the entire electrical system died you can still find your way back to Groton by following the shore until you recognize "home").

What about that other stuff? (Airspace, ToC/ToD, ETE, fuel burn, etc.)

There are a few important things you don't get by picking out the waypoints the way I did it above.  The most obvious one is Airspace -- you'll notice the course I've plotted cuts right through the Stewart (KSWF) Class D airspace, and Orange County is really close to the Class D ring. Unless you're in a helicopter there is no way you could fly above the Stewart airspace and then descend into Orange County along the plotted route without exceeding VNE, so you're going to have to plan on talking to Stewart's tower and requesting a transition. Note the tower and ATIS frequencies and pick a spot along your course to call the tower up to request the transition. (Same goes for the return trip - we plan to cut through right over the airport so we need to call them and ask.)
Similarly you want to note the tower frequency of any airport you're passing so you can monitor it, and so you can call them up if something goes wrong. This information is on the chart, but printing it in big letters on your navlog makes it easier to find.

Something else most flight instructors want to see you including are Top of Climb and Top of Descent (along with a calculation of fuel used in the climb or descent) - you get this the day of the flight by determining what altitude you want to climb to (based on the wind data you got in your pre-flight briefing) and referencing the aircraft's performance charts. You'll add a little mark to the course line on your chart for TOC and TOD, and I usually put it in a "notes" area on my navlog (TOC xx minutes elapsed and if there's a convenient visual reference I note what it is).

  General Tip: I try to include some waypoint that will be at or near top-of-climb/top-of-descent on my flight plans - if you have a reasonable idea of how your plane performs you can usually pick something within a few miles for most reasonable wind conditions. Doing that makes it easier because I can use the time-fuel-distance charts in the POH to fill in the estimated time enroute to that waypoint (or waypoints if it's a long climb) and the fuel burn: One less thing to calculate.
  I did not go out of my way to do this on the charts above.

You should also be calculating an estimated time enroute between each waypoint based on your calculated groundspeed (again you'll work this out before you depart based on forecast winds - you'll see that Skyvector computed it for us based on a 100-knot airspeed and the wind data available as I was typing this).
This seems a litle crazy for 10 to 30 mile legs like this (about 6 to 20 minutes enroute between each waypoint, but if we go back to the idea of using this navlog over a wide-open desert we may have an hour or more between waypoints, and cross-checking estimated time versus actual time lets you know if the winds are significantly different from the forecast values.

The estimated time enroute in turn gives you your fuel burn for each leg: You know your engine burns a certain number of gallons per hour, and you know how many hours (or fractions of an hour) each leg will take - multiply to get your fuel burn.

  Don't Run Out Of Gas Tip: Plan conservatively: Round fuel consumption numbers up to the next half-gallon or gallon.

Finally every navlog has at least one other key element: The heading you should be flying: True Course ± Magnetic Variation ± Wind Correction Angle ± Compass Deviation = Magnetic Heading - What you steer on the compass. Skyvector calculated this for us (with the exception of the Compass Deviation which it can't know) but if you're doing the flight plan manually you need to do this math yourself.
Again you would do this right before your flight, with the most current wind data.


Under what legal standing can after-hours ground access to an airplane be forbidden? (USA-specific only)

As per my answer here the FAA does define "Public Airport" but does not specify that ground access must always be available. The answer mentioned in the question, you link here covers the general scenarios where issues could crop up:

Private Airports: Are generally free to make rules as they see fit and could potentially prevent you from entering the property even if the tie down they offer is free. There are lots private airports in the US and there are even some big airports that are privately owned. Private airports while conforming to certain federal aviation regulations may ultimately be built on private land which falls under different (often local) regulations.
Ports Of Entry: An airport that has customs facilities may prevent you from accessing your aircraft prior to clearing customs or if they have another reason not to let you onto the ramp. This can get tricky as its often administered by the TSA.
Local Regulations: Airports are often owned by local governments or port authorities there is nothing preventing them (as far as i know) from making a rule/regulation that prevented field access at certain times.

The most frustrating issue in my experience is the "Private FBO" problem. Often times airports are publicly owned but physical ramp access is handled by Private FBO's that may chose to not be open 24/7 or may (what sounds like in your case) station a clueless guard at the gate after hours. This creates more of a practical issue than a regulatory one, either the owning authority needs to mandate the FBO allow people onto the ramp at all hours or the FBO needs to step up their game a bit when it comes to educating their employees.
I'd say 8/10 times the gate code is the CTAF frequency...


Would this work to reduce turbine engine spool times?

Short answer: no, none of what you describe is possible with current jet engines. You need more fuel because the angle of attack for your prop is increased, not the other way round.

Let's first go into some (simplified) detail how the turboprop works. A turboprop is basically a gas turbine engine with a propeller stuck on the axle. The propeller is the bit that converts the torque and rpm of the engine shaft into a forward thrust. The amount of forwards force is determined by RPM and blade pitch. This means that, even though you're at high RPM, you can 'feather' your propeller so that it doesn't produce any forward thrust (blades flat). At the same RPM, you can just put your blades so that they produce a lot of thrust. Of course, this comes at the cost of increased drag, so the engine has to 'work harder' to maintain RPM. This, in turn, is achieved by injecting more fuel.

Now, to a turbojet. For a turbojet, the thing that produces thrust is exhaust gas going backwards real fast. This is achieved by burning fuel so that the gas gets hot and expands, so that it wants to get out of there as fast as possible. For this, a jet engine needs a lot of air. It sucks in this air by a series of compressors at the front of the engine. Then, some fuel is injected, and after that there are some turbines that make sure the compressors can, and after that there's a nozzle that converts the leftover energy into backwards gas velocity. Now, we want to increase the thrust. This means that gas has to get out of the back faster. Since the nozzle is generally fixed, this means that you just have to get more air out of the back (just like a garden hose with the tap half open or full open). This means that we'll have to suck in some more air from the front, burn some more fuel to make sure the engine keeps spinning, and more air will come out of the back.

Simply increasing the fuel flow doesn't work. Jet engines operate 'lean' (more air than necessary), and the extra fuel you suddenly inject will burn up with all the excess air, which might blow up your engine. If your engine doesn't blow up, you're left with too little air to burn all the fuel, and you'll get a lot of nasty things like soot, carbon monoxide and unburnt fuel coming out of your exhaust. This means you just inject some extra fuel, wait for the engines to 'spool up' so they suck in more air, and like that gradually increase your engine RPM and linked to that the gas velocity.

Two things remain: why use fixed nozzles? This is because physics dictate that, for engines to be efficient, the exhaust velocity needs to be as high as possible; in practice, the exhaust velocity will be as close as possible to the speed of sound in the hot flue gas. Using a variable nozzle would mean that your engine never works efficiently at half power. Furthermore, it adds complexity, weight and thus costs more.

Another thing: I discussed turbojets, not turbofans. In theory, one could have variable blade pitch on a jet engine. However, remember that the fan is not just for thrust (even though high-bypass engines are generally more efficient), but also to make sure enough air enters the compressors; 'feathering' them would mean that your engine might not get enough air. However, your engine would need a lot of air, because it needs to operate very lean to make sure it can handle the extra fuel flow for when you increase the blade pitch. Furthermore, a variable pitch on all blades would mean a lot of complex engineering, which would make the engine a lot heavier.

Long story short: one could design jet engines with variable pitch, but the above wall of text is only the beginning of why that is an engineering nightmare. Without variable blade pitch or nozzles.


Where does it say that type certificates are required?

I guess I was thinking about it the wrong way. I was hoping for a single regulation to cover it. These sections of the FAR seem to be enough to say that type certificates are required for aeronautical products.

14 CFR §21.45 states the privileges bestowed to type certificate holders including the ability to obtain airworthiness certificates for aircraft, install engines and propellers, obtain production approval or replacement part approval.

14 CFR §21.6 states the need for a type certificate in order to manufacture new aeronautical products

14 CFR §21.9 states replacement and modification parts need to be produced under type certificate

14 CFR §21.132 states that a type certificate is necessary in order to be eligible for a production certificate.

14 CFR §21.183 states that in order to get an airworthiness certificate the aircraft must conform to its type design.

There are probably more examples in other sections. Any other answers appreciated.


Do fighter jets have forward-looking radar warnings for missiles, and when was this first implemented?

Radar Warning Receiver systems (RWRs) used by military aircraft are omnidirectional. However, they do not warn of incoming missiles (unless that missile is at least semi-actively radar-guided, like an AMRAAM). What they warn of are various patterns of radar activity, including a radar lock (which is a constant, high-intensity scanning of the aircraft's position, more than just a "blip" as the antenna passes by on a wide-angle scan pattern).

If another aircraft has a radar lock on you, you should be expecting an incoming missile of some kind. However, IR missiles (AIM-9 Sidewinder, AA-11 Archer, MICA IR, ASRAAM) do not emit any EMR that indicates they're incoming; they use a passive FLIR sensor to identify and track the heat source they were told to kill (they don't even require a radar lock; the seeker can be cued to a pilot's helmet, or it can be "uncaged" and will lock on to the most significant heat source in front of it). Passive radar-guided missiles like the old AIM-7 Sparrow also do not emit their own radar; they track the radar returns from the firing aircraft. Only semi-active and active radar-homing missiles emit their own radar noise that can be used by the RWR to know one is on the way. A few older passive missile systems used radio control to guide the missile to the target, and RWRs can also detect these "sideband" radio signals as a clue a missile has been launched.

More modern Missile Approach Warning Systems (MAWS) have additional features that can help detect and track incoming missiles of multiple types. The biggest clue of a missile launch is a new heat signature, especially in the direction of an incoming radar lock; a suite of IR sensors can be used by MAWS to put 2 and 2 together and warn you of the missile launch.


How do airplanes regulate the output frequency of AC generators?

It's done using mechanical device called constant speed drive. Works almost the same as CVT transmission in a cars. The more complex thing is phase adjustment as airplane usually has multiple engines and generators. But that is not done as different generators always power different buses!


Descent of Light attack aircraft to loiter altitude

I cannot answer for the Supertocano, or even light attack aircraft, but I can tell you that in a tactical environment nobody cares about your rate of descent or descent angle, only that you are in your assigned block altitude at the appropriate time.
Descents aren't planned or adhered to in same way that airline descents are, and fighter type aircraft aren’t controlled in the same manner.  There is no need to be smooth for paying passengers either - As long as airspeed and G restrictions for your type aircraft are followed, and you don’t violate any theater safety rules, (like blowing through another airplane’s block altitude while they are on station) the area commander just needs you to be on-station, on-target, on-time.
One day you might make an easy cruise descent, the next you might do a split-S.  The threat environment plays a part as well.  You may have the luxury of making a long easy fuel efficient descent, or you may need to stay high to avoid ground threats, then expedite your descent overhead your station.
I used to like to make a slow descending barrel roll because it was a good way to lose a lot of altitude quickly while visually clearing the airspace 360 degrees around me.


What would happen if thrust reversal is accidentally deployed during a flight?

If the aircraft is at cruise altitude and speed, the wing will see a large loss of lift, and will become uncontrollable.
It used to be possible to deploy thrust reversers in Boeings. It was not feared as a problem, since early tests showed that accidental deployments were survivable and the plane would stay controllable. However, these tests were only performed at low speeds, since low-speed deployments were assumed to be the most critical (source).

But then in 1991 Lauda Air 004 crashed mid-flight in Thailand after an uncommanded thrust reverser deployment. After this crash, additional safety features such as mechanical positive locks were mandated to prevent thrust reverser deployment in flight.
I'm not sure about Airbus, but I guess all current aircraft have some kind of lock.

Because engines on modern aircraft are so closely attached to the wing, the thrust reverser exhaust flow is right in front of the wing. Therefore, the wing will see a lower flow speed which results in a loss of lift.


Which airfoil to use for high subsonic flight?

Yes, you chose the wrong airfoil.
While the NACA 6-digit series was among the first set of airfoils computed from a design pressure distribution, they will suffer from shocks when operated above their critical Mach number just as any other airfoil.

Comparison of drag rise over Mach for 6-series and early supercritical airfoils from NASA Technical Paper 2969. It should be obvious which one is to prefer.
When transsonic research started, inverted airfoils paradoxically turned out to perform better at moderate lift coefficients and high Mach numbers than regular airfoils. Key is the low curvature on the suction side which makes a shock-free pressure rise possible. Practical designs aim for a weak shock over a range of lift coefficients. In oder to produce the most lift at a give Mach number, the pressure difference between upper and lower side can be maximized where thickness is low, i.e. in the rear area of the airfoil. This is called "rear loading". Supersonic flow on the upper side allows to create more lift over the full chord. On the most recent designs another small lift contribution results from a slower pressure drop on the forward edge of the lower side pressure distribution (the forward lower-surface undercutting of Phase 3 airfoils).

Effect of forward lower surface undercutting, from NASA Technical Paper 2969. The added lift at the forward part also lowers the pitching moment of supercritical airfoils.
Supercritical airfoils have negative camber over most of their forward part and strong positive camber only in the rearmost 20 - 30% of their chord. This NASA report (PDF!) lists a range of supercritical airfoils with different thicknesses and design lift coefficients. But it can only serve as a starting point since wing sweep will change the pressure distribution locally and demands a shift in the point of maximum thickness (forward at the root, backward at the tip) and more negative camber at the root in combination with a higher local incidence.
Mach 0.9 is only used by business jets where owners care more about bragging rights than fuel consumption. Airliners normally fly at Mach numbers ranging between 0.78 (short range) and 0.84 (long range) and for best efficiency should stay below Mach 0.82. They fly a bit above their drag divergence Mach until the gains in speed are balanced by the losses in drag. Of course, they can be operated at higher speeds but do so only to make up for a delay.


If left stationary at a specific height, would altimeter change the displayed value over time?

You are correct in both regards -- as Terry's comment points out, an undisturbed pressure altimeter's reading (imagine one sitting on a bench outside the local hangar) will change with the local barometric pressure.  TSO'ed "sensitive altimeters", i.e. ones with a hundreds pointer, not just a thousands, are required to have a knob and window, called a Kollsman window, for setting the local barometric pressure, or standard pressure (29.92) when above the transition altitude (18,000' in the US, check with the local aviation regulator for where you are in the world).  "Glass cockpit" systems have a knob/function for the same job -- whether it be a dedicated knob, or a mode on a multi-function knob.


How can I legally land VFR in class D airspace with low and few clouds?

What is the appropriate way to handle this situation as a pilot?

First, tell tower about the problem.  They may be able to assign you a different runway, have you loiter (circle) for a minute or three, etc.  It's likely not the first time this has ever happened.

If necessary ask the tower for a Special VFR clearance.  That changes your cloud clearance requirements dramatically in your favor.  Note that the tower is not allowed to offer this clearance to you - you have to explicitly ask for it.

  I'm calling up tower before I have a visual on the airport (which would be the case in this situation) would they likely deny clearance to land due to knowing that a singular cloud sits out there and would cause a bust the visual flight rules or might they clear me without regard to the rules?

J. Hougaard answered this part in the comments - the tower is likely not checking how far you are from a single cloud.


This diagram clearly shows it would be almost impossible to fit nine crew plus an additional twenty-six people in the aircraft. There are no seats for the additional twenty-six. At most you can fit two additional people in the observer seats behind the power distribution packs. The additional seats in the middle are for crew only during takeoff and landing. The aft cabin only has one seat for the mission planning workstation, and that's one of the nine crew seats.


Why wasn't the Boeing 737 grounded in 1991 after a crash's cause remained unknown?

If the cause of the accident can't be established, it can't be established it's due to a flaw in the aircraft itself, let alone a flaw in the aircraft design that affects the entire fleet.

For example there was an accident involving an aircraft where a careless maintenance worker had installed the wrong screws to refit a cockpit window. In your scenario the entire fleet would have been grounded instantly after the accident, pending investigation.In this case they found the cause of the accident after a few weeks, but in other cases it could take months or years and ruin not just every single operator of the type but the manufacturer as well.

Think MH370 for example. That one went down several years ago now and no wreckage was ever found to investigate. In your world that'd mean that every single Boeing 777 the world over would have been grounded now for several years and probably will never be allowed to fly again because it's extremely unlikely they'll ever find the wreckage, let alone in a state that will allow the determination of the cause of the crash.

In the years since, there's been 1 other crash of a Boeing 777, and that one due to external forces (a missile fired at it by the Russian army) completely unrelated to the aircraft itself.

Now, if there'd been a number of unexplained accidents due to mysterious causes in short order across operators of the same type, it's quite possible that operators, manufacturers, and regulators would step in and decide to suspend operations of that type pending investigation. But a single accident? No.


How long do airliner tires last? Can this be improved?

I've heard that airliners' tires will last about 200-250 depending on how many hard landings are made. Bizjet tires will last longer, and light aircraft tires will last indefinitely, depending on how gentle you are and what kind of surface you're landing on. I had one start cracking around the wall and just looking unsafe long before the treads ever started to wear.

As for the spin-up idea, it's been proposed many many times, but generally always rejected due to weight and maintenance costs. However, now that fuel is by far the main expense in an airliner's trip, companies are looking for any way to reduce fuel burn. As it turns out, taxiing an airliner burns quite a bit of fuel. They've already started turning one engine off for long taxis, and I think that electric wheel motors will be the next big thing.

The motors have gotten light enough and strong enough that they are a now a viable option. They can be powered by the APU or by a set of batteries (which are also now becoming light enough, see the 787 when they get the kinks worked out). So when they get around to putting them on aircraft for taxiing purposes, you can bet that they'll be spun-up right before landing.


How many type ratings are pilots allowed to hold at once?

There is no limit to the number of type ratings that a person can hold. The world record for most type ratings held by an individual currently stands at 105!

For safety reasons, most airlines only allow a pilot to be currently assigned to two aircraft types at one time so that they don't start to confuse the different airplanes and mix things up. This isn't a regulation though, at least in the US.

In your example, those airplanes are the same type so would only count as one of the two that they could be assigned to, but this will vary based on individual airline policy and the complexity of the differences between the actual aircraft involved.


What does 00 mean on a sectional below the airport runway information?

That is the elevation and length of the longest co-located water runway.  Elevation of 00, and runway length 5000 feet.

This information is found on page 16 in the current Aeronautical Chart Users Guide, which states:

  Runway length is shown to the nearest 100', using 70 as the rounding
  point; a runway 8070' in length is charted as 81, while a runway 8069' in length is charted as
  80. If a seaplane base is collocated with an airport, there will be additional seaplane base
  water information listed for the elevation, lighting and runway

(emphasis mine)

In this particular chart of Honolulu Int'l, the first line of airport runway info indicates 13 L 123, which is a 13 foot elevation, lighting in operation from sunset to sunrise, and 12,300 foot longest available runway.

The next line down, which you are asking about, is the "additional seaplane base water information", described by the ACUG.