BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to protection against terrorist bombing of aircraft and in particular to construction of aircraft and luggage facilities for directing explosive forces from bombs out of cargo holds safely and inexpensively without occurrence of injury to passengers or debilitating damage to aircraft. 
     2. Relation To Prior Art 
     Terrorist bombing of aircraft is proliferating in present world conditions. An effective and relatively inexpensive protection of passengers and aircraft against potential harm from luggage-borne bombs is critical. It can discourage their use in addition to protecting passengers and aircraft. 
     Solutions to date have included bomb-detection systems and explosion-containment systems. None have provided construction of aircraft and cargo facilities to direct explosive forces out of aircraft without occurrence of injury to passengers or debilitating damage to aircraft in a manner taught by this invention. 
     The most nearly related devices and systems known are those directed at containing explosive forces within aircraft. Examples of these different but related devices for differently protective systems are described in the following patent documents. 
     U.S. Pat. No. 5,360,129, issued to Lee, described an explosion-containment luggage container with explosive-containment construction on all but one or more weak faces through which explosive forces could be directed against a section of aircraft hull. There was no provision for construction of aircraft to allow escape of the explosion forces without flight-debilitating damage. U.S. Pat. No. 5,267,665, issued to Sanai et al taught an explosion-resistant luggage container that deformed spherically to aid in absorbing explosion pressures and explosion debris. Neither of these explosion-containment devices have been adequate. Luggage bombs and fear of their use continue to proliferate. 
     SUMMARY OF THE INVENTION 
     In light of need for a better system of protection against luggage-bombing of aircraft, objects of this invention are to provide an aircraft-luggage-bomb protection system which: 
     Directs explosion pressure and particles from aircraft-luggage bombs out through blow-away plugs in walls of airplanes; 
     Allows aircraft to be operated safely after in-flight detonation of luggage bombs planted by terrorists; 
     Provides quick and optionally automatic in-flight replacement of blow-away plugs; 
     Limits a luggage-bomb explosion to a single luggage-cart portion of an aircraft cargo hold; 
     Prevents in-flight explosion of luggage bombs from having a debilitating effect on either aircraft or aircraft passengers; 
     Is more effective and costs less to implement than other luggage-bomb-protection systems; 
     Can be implemented quicker than other systems of protection against luggage bombing; 
     Does not require development of untried and unknown protective systems; 
     Is less vulnerable than other systems to human error and ability of airline employees; 
     Minimizes criticality of luggage-bomb detection at airports; and 
     Can be used in combination with luggage-bomb detection as desired. 
     This invention accomplishes these and other objectives with an aircraft-luggage-bomb protection system having a blow-away plug for each of a plurality of luggage-storage units of a cargo hold of a commercial airplane. Luggage is placed in explosion containers that are positioned over the blow-away plugs. The explosion containers can be structured for select handling equipment such as luggage carts and pallets. The cargo holds are structured for quick and easy conversion between passenger use and airfreight use of planes. Procedural methods are provided. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     This invention is described by appended claims in relation to description of a preferred embodiment with reference to the following drawings which are described briefly as follows: 
     FIG. 1 is a partially cutaway perspective view of an airplane having blow-away plugs and a rail system for positioning explosion containers on luggage carts; 
     FIG. 2 is a partially cutaway section view of a cargo hold of an airplane in which explosion containers on luggage carts are positioned on blow-away plugs; 
     FIG. 3 is a partially cutaway top view of an explosion container on a cart with retractable wheels; 
     FIG. 4 is a side view of the FIG. 3 illustration with a pressure-containment door hinged open; 
     FIG. 5 is a partially cutaway sectional view of a side of a cargo hold over which an explosion-containment shell is positioned over a blow-away plug with hinged doors on a bottom of an airplane; 
     FIG. 6 is a partially cutaway sectional view of a side of a cargo hold over which an explosion-containment shell is positioned over a blow-away plug having a cross-sectional area approximately equal to a cross-sectional area of an entry to the explosion-containment shell; 
     FIG. 7 is a side elevation view of a stack of explosion-containment shells; 
     FIG. 8 is a top view of either a single or a stack of explosion-containment shells; 
     FIG. 9 is a partially cutaway side view of an explosion-containment shell attached to a loaded luggage pallet and being handled from a top by a lift vehicle; 
     FIG. 10 is a partially cutaway side view of a loaded luggage pallet positioned to be covered with an explosion-containment shell and being bottom-handled with a lift vehicle; and 
     FIG. 11 is a partially cutaway top view of a luggage pallet. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Reference is made first to FIGS. 1-2. Blow-away plugs 1 are positioned in line with an entry to explosion containers 2 in which luggage 3 is placed in a cargo section 4 of an airplane 5. The explosion containers 2 are structured and positioned to contain explosion pressure from a detonated luggage bomb while directing explosion pressure to the blow-away plug 1. The blow-away plug 1 is structured and positioned to be opened designedly by explosion pressure from a detonated luggage bomb in the cargo section 4 of the airplane 5, such that explosion pressure from a detonated luggage bomb in luggage 3 is contained by the explosion container 2 while the explosion pressure opens a wall section 6 and a surface section 7 of the blow-away plug 1. 
     Referring to FIGS. 1-4, the explosion containers 2 can be luggage carts 8 on wheels 9 which can be retractable and can be structured to run on rails 10 to be positioned over the blow-away plugs 1. Explosion containers 2, such as luggage carts 8, are fastened to a floor wall 11 with preferably a pressure-containment fastener 12 that is spring-loaded with a recoil spring 13 having spring force positioned in resistance to increase in distance intermediate a connection of the pressure-containment fastener 12 to the floor wall 11 and a connection of the pressure-containment fastener 12 to the explosion container 2 at a top of the luggage cart 8. 
     The recoil spring 13 absorbs explosive shock of initial peak pressure of explosion. This decreases required pressure-resistance and resulting weight of the explosion container 2 such as the luggage cart 8. 
     An explosion-escape chute 14 can be employed to provide communication of explosion pressure with an easy escape to the blow-away plug 1 from a luggage bomb in luggage 3 at any position within the explosion container 2. Grillwork 15 or other porous or easily breakable wall on the explosion-escape chute 14 can be employed to keep luggage 3 from clogging the explosion-escape chute 14. 
     Explosion pressure of expanding gas from a bomb expands spherically outward initially but follows least lines of resistance that may exist. A least line of resistance that is sufficiently large and free-flowing in a single direction can cause a flow of gas pressure in that single direction. The flow of gas pressure in such a single direction can diminish pressure in other directions to a point of negative or near-negative pressure in some explosion-containment conditions. An adequately quick, easy and large escape route is provided by the explosion-escape chute 14 and the blow-away plug 1 for this embodiment. 
     The wall section 6 of the blow-away plug 1 can be a circular plate that is seal-fastened with an O-ring 16 in a plug aperture 17 that is cylindrical at a connection perimeter and adequately reinforced. Fluidly downstream from the connection perimeter, the plug aperture 17 can be enlarged with a desired geometrical form to allow the wall section 6 of the blow-away plug 1 to travel without restriction from friction contact of the O-ring 16 with an internal periphery of the plug aperture 17. Shatter connections can be provided in lieu of the O-ring 16 and the wall section 6 also can be disintegrative in order to minimize obstruction of gas flow and to facilitate gas flow to the surface section 7 of the blow-away plug 1. 
     The wall section 6 of the blow-away plug 1 can be shatter-attached, hinged or attached otherwise to the airplane 5 in a manner that allows the wall section 6 to open or to be removed quickly and easily enough to facilitate directional flow of gas pressure from a detonated luggage bomb. 
     A pressure-containment door 18 with pressure fasteners 19 can be hinged to the luggage cart 8 to allow bomb-sealed placement and removal of luggage 3. 
     Referring to FIG. 5, the explosion container 2 can be an explosion-containment shell 20 with unitary construction, rounded corners, tapered walls and a domed top 21 to minimize weight per strength and to maximize effectiveness of directing explosion pressure in a single direction of flow towards a container entry 22. The luggage 3 can be stacked on a luggage pallet 23 having a center section 24 that is designedly open or openable above a wall section 6, a surface section 7 and a plug aperture 17 of a blow-away plug 1. 
     A shell-fastener means such as a fastener flange 25 on a bottom of the explosion-container shell 20 and a spring-loaded fastener bolt 26 in design pluralities can be provided to seal-fasten the explosion-container shell 20 to the floor wall 11 of the cargo section 4. With the explosion-container shell 20 seal-fastened to the floor wall 11, the center section 24 of the luggage pallet 23 can be used either in place of or in combination with the wall section 6 of the blow-away plug 1. The wall section 6 depicted for use with this embodiment is rectangular and has disintegrative fasteners 27 to a rectangular plug aperture 17. 
     An explosion-escape chute 14 with grillwork 15, as described in relation to FIGS. 2-4, is preferable for use with a center section 24 of the luggage pallet 23. 
     A surface section 7 of the blow-away plug 1 can be hinged with plug hinges 28 to the plug aperture 17 or to the airplane 5 proximate a bottom portion of the plug aperture 17. The plug hinges 28 and oppositely disposed walls of the surface section 7 are preferably parallel or substantially colinear to flight axis of the airplane. Wall actuators 29 can be employed to pivot the surface section 7 back to normal after a luggage-bomb explosion has expelled contents of the explosion-containment shell 20 or other explosion container 2 out of the airplane 5 through the blow-away plug 1. The wall actuator 29 can be operated with a torsion spring automatically or with hydraulic, pneumatic or mechanical means in accordance with design preferences. 
     An airplane 5 can continue flight without debilitative effect of a luggage bomb when the surface section 7 is closed and an explosion container 2 such as an explosion-containment shell 20 or a luggage cart 8 are seal-fastened to a floor wall 11. 
     Referring to FIG. 6, an entire luggage pallet 23 and its contents can rest on pressure-release latches 30 in line with a full-pallet plug aperture 31 and a full-pallet surface section 32. This provides full-pallet release that obviates need for an explosion-escape chute 14. The pressure-release latches 30 and a full-pallet surface section 32 can be pressure-sensitive to open and jettison the luggage pallet 23 and its contents with a designedly small fraction of explosion pressure from a detonated luggage bomb. Seal-fastening of the explosion-containment shell 20 to the floor wall 11 also obviates need for a wall section 6 in a blow-away plug 1. Passengers might not notice explosion of a luggage bomb as an airplane 5 continued on in flight. 
     Referring to FIGS. 7-11, tapered structure of an explosion-containment shell 20 allows a plurality of them to be stacked telescopically as depicted in FIG. 7. An explosion-escape chute 14 depicted by dashed lines in FIG. 8 is optional, depending on the type and size of blow-away plug 1 employed as described in relation to FIGS. 2 and 5-6. 
     A luggage pallet 23 can have a gate 40 in pallet walls 33 for loading luggage 3. The lift apertures 38 can be extended from-side-to-side as shown or partway through in accordance with the type of lifting mechanism employed. For using a boom 35 type of lift, the lift apertures 38 need only extend inwardly far enough to contain pressure-release fasteners 39. For versatility allowing use of either tines 37 or a boom 35, the lift apertures 38 can be extended from-side-to-side as shown. If employed, an explosion-escape chute 14, described in relation to FIGS. 2-3 and 5-6, can have a grillwork 15 on top as well as on sides to keep out luggage. 
     To use the explosion-containment shell 20, luggage 3 can be placed within pallet walls 33 on a luggage pallet 23. Then an explosion-containment shell 20 is positioned on the luggage pallet 23 as shown completed in FIG. 9 and in process in FIG. 10. If the luggage-containment shell 20 is fastened securely to the luggage pallet 23, a loaded luggage pallet 23 can be top-carried from a shell handle 34 with a boom 35 on a mobile lifter 36 as depicted in FIG. 9. If the explosion-containment shell 20 is not fastened securely to the luggage pallet 23, a loaded or unloaded luggage pallet 23 can be carried with tines 37 of a mobile lifter 36 inserted in lift apertures 38 in the luggage pallet 23. Optional to a motorized mobile lifter 36 depicted in FIG. 10 for lifting and moving a loaded or unloaded luggage pallet 23 not fastened to an explosion-containment shell 20 can be a hand-operative or walk-along lift that is not shown. Attachment of the explosion-containment shell 20 to the luggage pallet 23 can be accomplished with pressure-release fasteners 39 that can be used in lieu of or in combination with pressure-release latches 30. 
     A new and useful aircraft-luggage-bomb protection system having been described, all such foreseeable modifications, adaptations, substitutions of equivalents, mathematical possibilities of combinations of parts, pluralities of parts, applications and forms thereof as described by the following claims and not precluded by prior art are included in this invention.
An aircraft-luggage-bomb protection system has a blow-away plug (1) for each of a plurality luggage-storage units of a cargo section (4) of a commercial airplane (5). Luggage (3) is placed in explosion containers (2, 8, 20) that are positioned over the blow-away plugs. The explosion containers can be structured for select handling equipment such as luggage carts and pallets (23). The cargo sections are structured for quick and easy conversion between passenger use and airfreight use of planes. Procedural methods are provided.