WO1993019984A1

WO1993019984A1 - Aircraft fuselage flame barrier

Info

Publication number: WO1993019984A1
Application number: PCT/US1992/011229
Authority: WO
Inventors: Thomas Roudebush; Duane Randall; George Danker; Robert Mcgeary
Original assignee: Akro Fireguard Products, Inc.
Priority date: 1992-04-02
Filing date: 1992-12-28
Publication date: 1993-10-14
Also published as: AU2802792A; WO1993019983A1; WO1993019912A1

Abstract

A fire resistant pillow block (10) which may be tightly wedged within the fuselage channels (50, 56) of an aircraft. The pillow block (10) is formed of a flame resistant outer covering (12) surrounding a core (14) of flame resistant material. The outer covering (12) includes at least one gas exit hole (57) to release gasses produced by the core (14) under high temperature. To enhance the mounting of the pillow block (10) mounting flaps (58, 60) may be secured to the exterior covering and fixed to portions of the fuselage. These flaps (58, 60) may be secured by clips (64) fixed to the fuselage and having extending studs (66) which pass through a hole formed in the flap (58). The fire resistant pillow block (10) will block the passage of flame within the channel and will reduce or eliminate the air flow within the channel (50, 56) which may feed a fire within the aircraft.

Description

AIRCRAFT FUSELAGE FLAME BARRIER

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates in general to fire prevention in aircraft. In particular, the present invention relates to a device for blocking the passage of fire, and reducing air currents for feeding such a fire, within the fuselage of an aircraft.

Description of the Related Art

Contemporary aircraft design dictates that the body of an aircraft have a roughly tubular shape. This shape is formed by a series of ring-shaped frames which are longitudinally spaced along the body. In cross-section these frames typically have an I-beam configuration with the two flanges being located at the radially inner (inboard) and outer (outboard) ends of the web. The frames are maintained in their longitudinal spacing by longitudinally extending stringers circumferentially spaced about the body. The stringers have a generally U-shaped cross- section with laterally extending stringer flanges extending from each free end. The stringers are located such that the cross bar of the U is substantially coincident with the radially exterior flange of the frames. This defines an exterior lattice to which the aluminum skin of the aircraft may be riveted.

With respect to the tubular body of the aircraft, the stringers have a radial depth much less than that of the frames. As such, the longitudinal placement of the frames is further strengthened by longitudinally extending stabilization straps extending between the radially interior flanges of the frames at circumferentially spaced locations. The stabilization straps may have a generally U-shaped configuration with the free legs of such a U being directed radially outward. At locations where the stabilization straps cross the frames, the legs of the U are bent substantially parallel to the cross bar (i.e., the strap is flattened out) such that the strap extends inwardly only a small distance greater than the radially interior flange of the frames. This allows paneling, such as Conolite®, to be mounted upon the radially interior flange of the frames, to define interior walls such as for a cargo bay. These interior walls protect hydraulic, electrical, and fuel lines which run in the annular channels defined by the skin, adjacent frames, and interior paneling.

However, these annular channels can also aggravate an aircraft fire. Due to the presence of the interior paneling, it would be very difficult to direct fire extinguishing chemicals into these channels. The channels may also allow air currents to feed a fire within the channel or at a location in communication with the channel. In view of this, it would be advantageous to provide a fire.resisting system within these channels.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a device for reducing the damage caused by fire in an aircraft.

Another object of the present invention is to provide a device which prevents flame passage along the channels within an aircraft fuselage.

Another object of the present invention is to provide a device which reduces or eliminates the passage of air through channels within a fuselage of an aircraft, which air could feed a fire in the aircraft. A further object of the present invention is to provide such a device which may be easily and quickly installed.

Yet another object of the present invention is to provides such a device which is securely maintained in the proper position within the aircraft. These and other objects are achieved by a fire resistant pillow block which may be tightly wedged within the fuselage channels of an aircraft. The pillow block is formed of a flame resistant outer covering surrounding a core of flame resistant material. The outer covering includes at least one gas exit hole to release gasses produced by the core under high temperatures. At least a portion of this interior material has resilient characteristics such that the pillow block may be securely wedged within the fuselage channel to form an interference fit. This interference fit will maintain the position of the pillow block within the channel, and additionally restrict or eliminate air flow through the channel. To further enhance the mounting of the pillow block, mounting flaps may be secured to the exterior covering and fixed to portions of the fuselage. These flaps may be secured by clips fixed to the fuselage and having extending studs which pass through a hole formed in the flap. Alternatively, the flap may be wrapped about a portion of the fuselage and a spring clip or deformable clip applied thereover to maintain the flap in position. The fire resistant pillow block will block the passage of flame within the channel and will reduce or eliminate the air flow within the channel which may feed a fire within the aircraft.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention noted above are explained in more detail with reference to the drawings in which like reference numerals denote like elements, and in which: Fig. 1 is a perspective view and partial cutaway of a device according to the present invention;

Figs. 2 and.3 are detail cross-sectional views showing alternative seam arrangements for the present device;

Fig. 4 is a cross-sectional side view of a device according to the present invention mounted within an aircraft fuselage; and

Fig. 5 is a cross-sectional view along line 5-5 of Fig. 4;

DETAILED DESCRIPTION OF THE INVENTION With reference to Fig. 1, the device according to the present invention is generally designated by reference numeral 10. The device 10 includes an interior mass 14 which may be surrounded by an outer covering 12.

The outer covering 12 should be formed of a material which is at least semi-flaccid and will withstand high temperatures, including flame impingement, for a reasonable period of time. For example, the material forming the covering 12 may withstand a temperature of approximately 950°C (1750°F) for 5 minutes without burning, although charring may result. One suitable for the covering 12 is a fabric produced by Firestop Incorporated of Chicopee, Massachusetts under Model No.

Another desirable characteristic for the covering 12 may be water repellency. Specifically, the metal fuselage tends to develop condensation which may seep into the material orming covering 12. This moisture may in time cause deterioration of the device 10. As such, the material noted above may be coated with a layer of silicone, possibly containing a fire resistant additive. Alternatively, the covering 12 may be formed of Bisco® produced by the Bisco Company of Elk Grove Village, Illinois. This material provides the desired flame resistance in addition to being water repellant.

While the general shape of the device 10 could take many geometric forms, it is preferred that the device be generally block-like in configuration. As such, the device will include an upper and lower face 16 and 18, inboard and outboard faces 20 and 22, and right and left faces 24 and 26. Where fabric-like materials such as those noted above are employed for the outer covering 12, various shapes of material pieces may be assembled together to form an appropriately shaped outer covering 12. For example, a single long and narrow strip of material could be employed to form the inboard, outboard, right and left faces, while two rectangular pieces would form the top and bottom faces 16 and 18. When assembled, this arrangement would result in a seam extending about the periphery of each of the faces 16 and 18 and a seam extending across, or at the intersection, of one of the faces 20 through 26. While many arrangements will provide a sufficient structure for the covering 12, the placement of the seams may affect the fire resistant property of the device 10. For example, in the arrangement described above, the anticipated flame impingement upon the top or bottom face 16 will result in the flame impinging upon the long seam which completely surrounds each of the spaces. As such, various other arrangements which present reduced seam lengths may be preferred. Specifically, in the arrangement shown in Fig. l, the outer covering 12 is formed by two pieces of material, such as those specific materials mentioned above. A first of these pieces of material forms the right face 24, the top face 16 and the left face 26. The other piece of material forms the inboard face 20, the bottom face 18 and the outboard face 22. As may be readily seen, this will result in the upper face 16 having a seam only along the inboard and outboard edges thereof. The bottom face 18 will have seams only, along the right and left edges, at the intersection of the right and left faces 24 and 26. This will result in a reduced length of seam for possible impingement with the flame. As it is believed most likely tha flames will impinge upon the bottom face of the device 10, this arrangement is preferred since the seams along this bottom fac are even shorter than those along the top face.

Another arrangement is to form the bottom face, righ and left face and inboard and outboard faces from a single piec of the material. Such a piece of material would have generally cross-shaped configuration. The top face would b formed by a single rectangular piece of the material. Thi arrangement would result in a vertical sew line at each corne and a sew line about the entire periphery of the top face. A may be envisioned, from the bottom only the ends of the fou corner seams would be subject to flame impingement. While the seam locations may be arranged for increase protection against flame and heat impingement, it is stil believed important that the seam structure include a fairly hig degree of flame resistance. Due to the very nature of typica materials used to form the outer covering, heat sealing to for the seams would often prove difficult, if not impossible. Adhesives containing flame retardant materials could b employed, but must remain flexible to retain the desire resilient feature of the device 10. Metallic fasteners such a rivets, studs or staples have a high temperature resistance, bu do not provide adequate protection against the ingress of water

In terms of flame resistance, strength, and wate repellents, an advantageous method to form the seals is to se the material portions together along the seams.

An example of such a sewn seam is shown in Fig. 2 where the inboard face 20 and top face 16 are sewn together with a length of thread 28. Various materials could be used for the thread 28. While standard textile threads are believed inadequate, thread having a high flame resistance may be formed of fiberglass, Nomex®, Kevlar®, stainless steel, or combinations thereof (i.e., a stainless steel thread core surrounded by a jacket of Kevlar®) . While the fire resistant properties of these thread materials vary, so do their cost and ease of working. The particular seam style at the sewed seam also has an effect upon the fire resistant properties, allowing threads of lower fire resistance and costs to be employed, yet providing a seam having the desired fire resistance.

For example, with reference to Fig. 2, it should be apparent that this seam would have greater fire resistance where the upper portion of the figure is the exterior side of the device 10, as opposed to the lower portion being exterior. This is because less of the thread material 28 will be exposed to the exterior, and thus the impinging flame and heat. Other seam arrangements may also provide further increases in flame resistance. For example, the arrangement shown in Fig. 3 is believed to provide greater flame resistance than the seam shown in Fig. 2. This is because the free edge of the material forming top face 16 will tend to force closed the gap which could form between the intersection of the inboard face 20 and top face 16, assuming that the upper portion of Fig. 3 is most exterior.

It should of course be apparent to those skilled in the art that other thread materials and seam arrangements could provide increased flame resistance.

As noted above, it is preferred to provide the outer covering 12 to surround inner mass 14. This inner mass is preferably formed of flame resistant material to provide further protection and safety. It is also preferred that the inner mass 14, alone or in conjunction with the covering 12, provide the device 10 with at least some degree of resiliency, for reasons noted below. As such, any material or combinations of materials which meet these dual requirements of fire resistance and resiliency may be employed for the inner mass 14. Examples of materials which may be employed or mass 14 are furnace grade fiberglass matting, silicone foam, or other resilient foams having flame resilient additives or properties. These foams could be provided in block form, as layers of sheets, or as a quantity of smaller pieces. It is also possible to employ more than one of these materials within a single device 10. For example, an inner layer of fiberglass matting could be surrounded above and below by a layer of foamed silicone. Yet another alternative is to fill the outer covering

12 with a fire resistant granular material such as Vermiculite, while providing a peripheral layer of resilient material such as silicone, foam or fiberglass along the inboard, outboard and right and left faces. It may also be possible to limit such resilient materials solely to locations adjacent the corners between such faces.

While the device 10 is preferably slightly resilient, forming the interior mass 14 of the materials described above may not provide sufficient strength for reasons noted below. In such situations the inner mass 14 may be provided with structural strengthening members. For example, the inner mass 14 may be formed of multiple layers substantially parallel to the top and bottom faces and consisting of top, middle and bottom layers 30, 32, and 34 of fiberglass matting or silicone foam. Interposed between each of these layers is a sheet 36 of a substantially rigid material, preferably having fire resistant properties. For example, the sheets 36 could be formed of Conolite®, a board formed of fiberglass and cured epoxy resin containing a fire resistant additive, ceramics, metals or other suitable materials. To retain the resilient characteristics of the device in a plane parallel to that of top face 16, it is preferred that the sheets 36 have a periphery smaller than that of top face 16, such that the peripheral edges of the sheets 36 are spaced inwardly with respect to the peripheral edges of the layers 30 - 34.

To provide further structural integrity and to insure that the sheets 36 to not abut against the interior face of the outer covering 12, thus impairing the resilience of the device, the sheets 36 may be secured to the foam layers, preferably by an adhesive containing fire resistant additives.

It should also be apparent that other arrangements providing a degree of structural stiffness to the device could be employed. For example, a single sheet 36 surrounded by a pair of silicone foam layers could provide sufficient stiffness.

The mounting of the device within the aircraft fuselage is shown in Figs. 4 and 5. As noted in the background of the invention section above, . the aircraft fuselage is substantially tubular in form and includes a plurality of longitudinally spaced ring-like frames 38. The frames 38 typically have a cross-sectional configuration of an I-beam, including a central web 40 extending between an outboard flange 42 and inboard flange 44. Extending longitudinally between the frames 38 are a series of circumferentially spaced stringers 46. The stringers are generally U-shaped in cross-section, having a cross bar and a pair of spaced legs extending outwardly therefrom, and further include a wing flange 48 extending laterally outward from each of these legs. As is best seen in Fig. 4, the cross bar of the stringer 46 and the outboard flange 42 of the frames 38 form an exterior lattice or framework to which exterior aluminum skin 50 is riveted.

To provide a more rigid structure, a series of longitudinally extending and circumferentially spaced stabilization straps 52 are connected to the inboard flanges 44 of the frames 38. The stabilization straps may be substantially flat bars, or may have a generally U-shaped cross-sectional configuration including a crossbar and a pair of legs extending outwardly therefrom. As indicated at 54, these legs are bent or flattened to be substantially parallel with the crossbar at those locations where the straps cross the inboard flanges 44, such that a substantially continuous annular face is provided at the inboard edge of the frames 88. In the cargo bay of aircraft this annular inner face provides a mounting for paneling sheets 56 which define the interior walls of the cargo bay. The paneling sheets are typically formed of Conolite® and serve to protect the hydraulic, electrical and fuel lines which run through certain ones of the channels defined by the skin 50, adjacent frames 38 and paneling sheets 56. It is within these channels that the device 10 is located.

As may be readily seen in Figs. 4 and 5, the device 10 is compressed within this channel such that it is held in place by an interference fit. Specifically, the outboard face 22 will abut against the skin 50 and the outboard flanges of the associated frames 38. The inboard face 20 of the device will abut against the interior of the paneling sheets 56 and the inboard flanges 44 of the associated frames. The right and left sides 26 and 24 of the device will abut against the webs 40 of the associated frames. The periphery of the device 10 is formed slightly larger than the cross-sectional periphery of the channel such that an interference fit is maintained. Due to the resilient nature of the device in a plane parallel to the top face 16, the device is securely held in place.

Given the types of materials which are typically used for the interior mass 14, it is possible that this mass will form a weakened line such that the device 10 will tend to fold rather than uniformly compress. It is for this reason that the substantially rigid sheets 36 may be employed. These sheets will prevent such folding and insure that an interference fit, and thus proper placement, are maintained.

The resilient nature of the device in general and the semi-flaccid nature of the outer covering 12 allow the device 10 to substantially conform to the interior of the channel, fully blocking this channel. As such, the device w ll serve as a flame barrier to prevent flames from passing along this channel and spreading. Additionally, the.device 10 will substantially reduce and in some cases eliminate air flow through the channel. This will eliminate a source of fresh oxygen for fires which are in the channel or in communication with the channel. This will help to reduce the spread of the flames, and will also reduce or eliminate any air currents which could push the flames towards sources of new combustible materials. As such, the device helps to greatly reduce the threat of fire within the aircraft.

Under the impingement of flame or at elevated temperature the material forming the mass 14 may give off gasses. Where the mass is surrounded by the outer covering, the outer covering may not allow escape of such gasses at a sufficiently high rate, causing the pillow to expand like a balloon due to increased pressure therein. This pressure may become sufficiently high that a seam of the covering, or the covering material itself, is ripped. Such uncontrolled expansion could reduce the effectiveness of the pillow.

To reduce such a possibility it is preferred that the outer covering include one or more pressure relief holes 57. The holes 57 may advantageously be formed as numerous small diameter holes or slits in the outer covering. It is preferred that the holes be formed through the face which is most likely to receive flame impingement(believed to be the bottom face) , so that the exiting gasses might act to blow the flames away, reducing flame impingement, and thus increasing the life of the pillow.

The formation of holes or slits through the outer covering would obviously have a detrimental impact upon the waterproof characteristics of the covering. This problem is reduced by forming the holes through the bottom face, but is not eliminated. To provide full waterproof effects, it may be necessary to plug the holes with a material which will prevent ingress of moisture, but will burn away or through which the expanding gasses may push. For example, a layer of silicone could be provided on the bottom face to cover the holes 57. The silicone would stop moisture, but would burn away, or be sufficiently weakened by high temperature, that the gasses could exit the holes.

It may be readily seen that the operation of the device is greatly dependant upon its blocking position within the channel. However, with deterioration associated with age and the imposition of vibration and mechanical shock common to an aircraft fuselage, there is a possibility that the device will become dislodged from its blocking position. This may also be aggravated by sudden or extreme pressure differentials caused, for example, by explosion or decompression of the bay. For this reason it may be desirable to provide additional means for securing the device within the channel.

A wide variety of means could be employed for this purpose. For example, the device could be adhesively secured in place, preferably with an adhesive containing fire resistant additives. Mating snaps could be provided, with a male member being mounted upon the web 40 and mating female member mounted upon the right and left sides 24 and 26. Still another arrangement would be to provide a hook and loop or mating T fastening systems between the device and surrounding channel walls. Such fastening" systems would preferably be flame resistant, and to this end the hook and loop fastening systems may be coated with a layer of latex containing a flame resistant additive, or the mating T fastening system could be formed of metal or other high temperature material.

Yet another arrangement for maintaining the device in place is illustrated in the figures. With reference to Fig. 1, the device 10 includes a pair of inboard mounting flaps 58 and a pair of outboard mounting flaps 60. Each of these flaps are mounted upon the top face 16 adjacent the associated face 20 or 22. The flaps may be sewn to the top face 16 using thread 28. The material used for thread 28 may be of a higher fire resistant than that used to form outer covering 1-2 where the flap thread is exposed as shown in Fig. 1. Alternatively, the flaps may be mounted by placing their mounting edge between the seam formed between the top face 16 and associated face 20 or 22. The sewing used to form the outer covering 12 would thus also mount the flaps 58 and 60. The flaps may be substantially rectangular as shown in the figures, or may take other configurations. A preferred arrangement is to provide a single inboard flap and a single outboard flap, each extending substantially along the entire length of the pillow, the flaps are substantially rectangular, but at least the inboard flap includes mitred corners.

These flaps may be employed for mounting the device in a manner as noted above, i.e., adhesive, snaps or other fastening systems. The flaps could also be employed for riveting the device in place.

A further mounting arrangement is shown in Figs. 4 and 5. The inboard mounting flaps 58 may be partially wrapped around the associated stabilization strap 52 and thereafter secured to this strap by means of a spring clip 62. The spring clip would have a generally C-shaped configuration and would be forced over the strap 52 and covering flap to partially surround same. To provide a strong hold with minimal weight it is preferred that two or more spring clips 62, each having a short length in the longitudinal direction of the fuselage, be employed. Alternatively or additionally, the flaps may be mounted to the strap using deformable clips. Such clips may be made of strips of thin metal. The flap would be wrapped about the strap as previously described, and the deformable clip plastically deformed about the strap and flap to at least partially surround same.

The outboard mounting flaps 58 are fixed to the associated stringer 46. Specifically, a stud clip 64 of known design and common use in the aircraft industry may be mounted upon the lower wing flange 48 such that the stud 66 of the clip 64 extends outwardly therefrom, preferably in an inboard direction.

The inboard mounting flaps 58 each include at least one through hole 68 which receives the stud. To strengthen the hole 68, the flaps, or one of the flaps 58, may include a reinforcement ring 70 of brass, steel, plastic, or other material. The flap may be secured upon the stud by use of a press fit ring 72 which firmly engages the free end of stud 66 to prevent removal therefrom, and thus disengagement of the flap or flaps 58. In actual use it may be found that the location of the stud clip 64 is determined by the location of conduits, insulation or other items within a particular channel. As such, it may be advantageous to form the through holes 68 on-sight by use of a hole punch or other means. In such a situation, the reinforcement ring 70 will be disregarded, or reinforcement ring elements which may be easily applied in the field will be supplied.

It should be noted that while a pair of flaps 58 and 60 are shown in Fig. 1, the device 10 may include three or more of each of these flaps. Alternatively, a single flap 58 and single flap 60 may be provided, as shown in Fig. 5. This single elongated flap may be preferred, due to its increased ability to block passage of flame and air currents.

Additionally, the relative location of the stringer 46 and stabilization strap 52 may vary between aircraft, aircraft type, or circumferential location within a single aircraft. As such, it may be advantageous to form the flaps 58 and 60 of a sufficient length to account for such various relative locations. It is also noted that the device 10 need not be placed at a location below the stringer and stabilization strap as shown in Fig. 4. For example, the device could be placed vertically above both of these elements, or only one of these elements. It is believed, however, that it is advantageous to place the device 10 at a location below, and in proximity to, a stringer 46. This is due to the condensation which tends to form on the interior of the skin 50. The stringers 46 tend to act as conduits and reservoirs for such collected condensation, and placement of the device immediately above a stringer may cause the device to come into contact with such collected condensation, or to be subject to increased amounts of condensation run-off compared to a location just below a stringer. Where the device 10 is placed above one or the other of the stringer or stabilization strap, such elements may serve to partially support the device against displacement and eliminate the need for connection of the associated flap. However, it is preferred that the flaps be employed.

It is also envisioned that the horizontal length of the right and left faces 24 and 26 may be reduced such that the device may abut directly against the stringer 46 rather than the skin 50. In such a situation, the outboard mounting flaps 60 may still be employed. In this arrangement the stud clip 64 may be mounted such that the stud 66 extends inboard of the fuselage, with the through holes 68 being placed close to the top face 16, or the stud 66 may extend outboard of the fuselage such that the flap 60 wraps about the wing flange 48 of stringer 46. It should be apparent to those in the art that, although the invention has been described with regard to specific embodiments, other arrangements are within the scope of the invention. For example, the blocking pillow may be formed without an outer covering where the inner mass is sufficiently cohesive, water repellant and fire resistant. Additionally, it is sometimes the case that insulating blankets are provided within the channels. Where such blankets are present they may be removed or cut away to install the device, the device may be mounted to the insulating material in manners similar to those noted above, or the device may be mounted with no consideration for the blankets, i.e. the flaps and clips are applied over the blankets.

From the foregoing it will be seen that this invention is one well adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.

Claims

WHAT IS CLAIMED IS:

1. A device for substantially blocking passage of flame and air current within a channel, comprising: an outer covering of flame resistant material, said covering defining an at least substantially closed cavity therein and said material being at least semi- flaccid; and an interior mass located within said cavity and comprising at least one flame resistant material.

2. A device as in Claim 1, wherein said outer covering includes at least one gas pressure relief hole extending therethrough.

3. A device as in Claim 1, further including means for fixing said device within the channel.

4. A device as in Claim l, wherein a peripheral length of said device is greater than a cross sectional peripheral length of the channel, and said interior mass includes at least a portion of substantially resilient material, whereby said device may be releasably retained within said channel by an interference fit.

5. A device as in Claim 4, wherein said interior mass includes at least one at least substantially rigid substantially planar sheet having a peripheral length less than that of said device, the plane of said sheet substantially including said peripheral length of said device.

6. A device as in Claim 5, wherein said at least one flame resistant material is in the form of discrete layers, at least one of said layers being in opposed abutting relation to a planar face of said sheet.

7. A device as in Claim 4, wherein said device has a general form of a block having a top face, bottom face, inboard face, right face and left face, and wherein said peripheral length of said device is measured along a plane substantially parallel to said top face.

8. A device as in Claim 7, further comprising means, in addition to said interference fit, for retaining said device within the channel.

9. A device as in Claim 8, wherein said retaining means includes: at least one inboard mounting flap having one edge fixed adjacent the intersection of said top and said inboard faces; at least one outboard mounting flap having one edge fixed adjacent the intersection of said top and said outboard faces; and respective means for fixing at least one of said inboard and said outboard flaps to the channel.

10. A device as in Claim 9, wherein said fixing means is associated with said outboard flap and comprises at least one stud clip having a clip portion adapted to be frictionally retained to the channel and a stud carried by said clip portion and having a free end extending therefrom, said stud extending through a hole in said outboard flap, and said outboard flap retaining means further comprising a locking member mounted on said stud with said outboard flap being interposed between said clip portion and said locking member, such that said outboard flap is fixed to said stud clip.

11. A device as in Claim 9, wherein said fixing means is associated with said inboard flap and comprises a clip adapted to be frictionally retained upon the channel, said inboard flap adapted to be interposed between said clip and the channel, and thereby retained.

12. In combination: an aircraft including a generally tubular body including at least two longitudinally spaced frames having a generally ring-like shape including radially outboard and radially inboard faces, an exterior skin extending between said outboard faces, and interior paneling extending between said inboard faces, thereby forming at least one fuselage channel defined by said frames, said skin and said paneling, said channel having a cross sectional periphery; and at least one device for reducing the spread of fire on said aircraft, said device comprising at least one flame resistant material, each said device having a periphery substantially corresponding to that of said channel, and wherein each said device being fixed within an associated one of said channels with said peripheries substantially aligned, whereby said device substantially blocks said channel.

13. The combination of Claim 12, wherein said device further includes an outer covering of flame resistant material, said covering defining an at least substantially closed cavity therein and said material being at least semi-flaccid, and an interior mass located within said cavity and including said at least one flame resistant material, and said device further including means for fixing said device within the channel.

14. The combination as in Claim 13, wherein said outer covering includes at least one gas pressure relief hole extending therethrough.

15. The combination of Claim 12, wherein a peripheral length of said device is greater than a cross sectional peripheral length of the channel, . and said interior mass includes at least a portion of substantially resilient material, whereby said device may be releasably retained within said channel by an interference fit.

16. The combination of Claim 15, wherein said interior mass includes at least one at least substantially rigid substantially planar sheet having a peripheral length less than that of said device, the plane of said sheet substantially including said peripheral length of said device.

17. The combination of Claim 16, wherein said at least one flame resistant material is in the form of discrete layers, at least one of said layers being in opposed abutting relation to a planar face of said sheet.

18. The combination of Claim 15, wherein said device has a general form of a block having a top face, bottom face, inboard face, right face and left face, and wherein ^aid peripheral length of said device is measured along a _^ane substantially parallel to said top face. _

19. The combination of Claim 18, further comprising means, in addition to said interference fit, for retaining said device within the channel.

20. The combination of Claim 19, wherein said 5 retaining means includes: at least one inboard mounting flap having one edge fixed adjacent the intersection of said top and said inboard faces; at least one outboard mounting flap having one 0 edge fixed adjacent the intersection of said top and said outboard faces; and respective means for fixing at least one of said inboard and said outboard flaps to the channel.

21. The combination of Claim 20, wherein said fixing 5 means is associated with said outboard flap and comprises at least one stud clip having a clip portion adapted to be frictionally retained to the channel and a stud carried by said clip portion and having a free end extending therefrom, said stud extending through a hole in said outboard flap, and said 0 outboard flap retaining means further comprising a locking member mounted on said stud with said outboard flap being interposed between said clip portion and said locking member, such that said outboard flap is fixed to said stud clip.

22. The combination of Claim 20, wherein said fixing means is associated with said inboard flap and comprises a clip adapted to be frictionally retained upon the channel, said inboard flap adapted to be interposed between said clip and the channel, and thereby retained.