announces a major breakthrough aircrf ... - Eaton …

1 * _____ ~~~0 AEBb t~ mqunpIeIAE AEROSPACE ENGINEERING BULLETIN 2 256 Bannounces amajor breakthroughinreducing approved aeroquip crashworthy fittings and flexible hose. Meets TSO C-53aamended for 250 psi operating pressure. Conforms to MDL Standard crashworthy fittingsprovide a new level of safety for general aviation aircraftNow, aeroquip engineering Army study proves Wknow-how makes it possible to crash-resistant fuelgreatly lessen the risk of post- systems save livescrash fires. Crashworthy hose Crash-resistant fuel systemsfittings that separate on impact, featuring crashworthy fittingsactuating a built-in safetyflapper -and flexible hose have beenhelppreventfuellossfromeither -used in Army helicoptersthe fuel lines or the fuel tank. since 1 970 with great suc-By containing the fuel in this cess.

2 By far the most impressivemanner, pilot and passengers .finding of the study revealed 52chances of escaping a post- .g fatalities and 31 fire relatedcrash fire are greatly injuries in crashes of helicoptersincreased. without crash-resistant fuelRedundancy has always been systems. However, in accidentsthe watchword in the design of of those equipped with crash-aircraft. Back-up in mechanical resistant fuel systems, therefunctions is vital to safety and were no injuries or fatalitiessurvival. This same concept like- caused by pertains to the / wesise of perain t Although the crash-resistantdesign of aeroquip ._fuel system has beencrashworthy hose fit-el syte has hoserovi f it , L ~ s '// * i lyin helicopters, itcanthe best protection avail- adaptedtofixed-wingable intime of critical aircraft as need to contain fuelon impact.

3 FAA research (FAA-RD-78-28)Even the best trained pilot is at into fuel containment for Part 23the mercy of mechanical failure aircraft has shown that .. crash-to some degree. When and if / l < resistant fuel cells used withafailureoccurs, thesmall self-sealing frangible fuel linecost of crashworthy hose fittings couplings can effectively reducewill indeed prove to be inexpen- postcrash fuel fires in generalsive protection. aviation aircraft. Therefore, the_ v//|Safety Board believes that theResearch shows safety / regulation should be amendedtofactor of crash-resistant require incorporation offuel systems with crash-resistant fuelcrashworthy fittings systems in generaland flexible hose. aviation to research conductedby the National Advisory Coin-mittee for Aeronautics (NACA),more than twice as many fatal-ities occur in crashes followed byfire than those without.

4 A studyby the National Transportation __Safety Board (NTSB-AAS-80-2)determined that postcrash firesare a much more significantproblem today than 30 years of 22,002 general aircraft 4>accidents revealed 59% of theaccidents involving postcrashfires resulted in fatalities. aeroquip Corporation 19912 aeroquip crashworthy hose fittingsO meet MIL-STD-1 290 for crash-resistant fuel systemsAeroquip engineersfaced with the challengeof developing products for crash-resistantfuel systems, began working on a solution inearly 1970. Crashworthy fittings are designed to breakaway onMIL-STD-1 290 specifications call for, in impact, at which time a built-in safety flapper closesaddition to crash-resistant fuel tanks, the to prevent fuel other fuel system requirements:1. Fuel lines consisting of flexible hosearmoured with braided Fuel systems, at critical failure points, tobe fitted with crashworthy, self-sealingbreakaway basic idea of the crash-resistant fuelsystem is to absorb energy on impact andminimize failures that result in the escapeof flammable fluids in a in 1 979, aeroquip developed a hoseassembly with a self-sealing crashworthyend fitting.

5 Research and study responsesfrom aircraft manufacturers indicated ahose assembly meeting a +2500F. temper-ature and 250 psi operating pressurerequirement would provide a level of safety Hose Assembly Sealedequivalent to TSO C-53a Type A and Cspecifications. aeroquip then retested itscrashworthy end fittings at +2500F. and apressure of 250 psi. All testing required byTSO C-53a for Type A and Type C hoseassemblies was satisfactorily completedand approved. Test reports are availableupon request. Proper selection of the correct crashworthy fittingstyle depends on the direction of the fuel flow in thesystem. See page and cost arenegligible in considerationof the safety fittings add minimal weight _and cost to the 'srequired istoremoveanexisting ATS0 approved hose assembly and replaceit with the new TSO approved crashworthyassembly without additional : Extremely important, however, isproper installation with consideration giventothe direction of fuel flow and proper fittingselection to contain fuel at fuel source in acrash mode.

6 Installation of aeroquip crash-worthyfittings should only be performed bylicensed A & P mechanics at an FAA/TSOapproved overhaul facility. Contact aeroquip Accessoy Sealedengineering for special design considera-tions and fittingsHOSE WIRE BRAID IS SAFETY FLAPPER ACTUATES SPLIT TUBE NIPPLE 0 COMPRESSED BETWEEN CLOSED FOLLOWING THE DESIGN SUPPORTSTHE SOCKET AND FRACTURE OF THE FRANGIBLE THE FLAPPER DURINGNIPPLE WHICH PROVIDES LIP WHICH IN TURN ALLOWS NORMAL RETENTION INDEPENDENT THE SPUT TUBE NIPPLE TOFROM THE FLU I D*UPSEAL.' DEFORM AN DPEEL OUT/DURING CRASH crashworthy hose fittings are available in For example, let's suppose a fuel line running from 0two different styles, "hose assembly sealing" and the fuel tanktothe fuel pump is connected atthe inlet''accessory sealing".

7 Proper selection depends on the port. If this inlet port fitting was accidentally knockeddirection of fuel flow in the system. The basic purpose off atthepumpa "hoseassemblysealing" crashworthyof the crashworthy fitting is to contain the fuel at the fitting would automatically seal the hose line, whichfuel source, helping to prevent spillage or leakage helps prevent further fuel spillage from the hose. Ifwhich would have the greatest potential of feeding a the accident had occurred on the outlet side of thefire in a crash mode. pump, an "accessory sealing" crashworthy fittingwould perform the same safety function."HOSE ASSEMBLY SEALING' 'ACCESSORY SEALING"Material and finish Forces required to actuateCrashworthy hose fittings are anodized aluminum. frangible sectionAll materials and finishes conform to applicablespecifications for end fittings used in aircraft fluid Tensile Bendingsystems.

8 To aid proper selection, flow direction arrows Size (Lbasd) Momentare impression stamped on the frangible section ofthe fitting. -6 220 -320 200 -400 Caution: To assure proper application due to differ-ences infuel lineroutingonvariousaircraft, installation -8 550 -750 450 -650of aeroquip crashworthy fittings should be performedbylicensedA& P mechanics atan FAA/TSO approved -10 550-750 450-650overhaul facility. In addition, the use of Aeroquipcrashworthy fittings does not guarantee a postcrashfire will not occur. Circumstances, such as metal fuel -12 650 -850 490 -690tank rupture or severing of fuel lines without or awayfrom the crashworthyfitting may cause the escape of Generally, the force required tofracture the frangibleflammablefluids in a crash. ContactAeroquip regarding section of the hose fittings is 50%, or less, of theforcerecommendations for specific applications.

9 Required to pull the hose out of the fitting fuel line installation with crashworthy fittingslC, , i~g CMIL-STD-1 290 specifications recommends fuel commonly used in aerospace systems. ThisC lines consisting of flexible hose armoured with hose retains its flexibility over a long period of-braided steel and crashworthy self-sealing time and has a practically unlimited shelf at critical failure points. The recom- AE701 hose is reinforced with strong stainlessmended hose for this application is aeroquip steel wire braid consisting of a partial innerAE701 * AQPTm hose. It consists of a seamless braid and full coverage outer braid. AE701 hosespecially formulated synthetic compound inner assemblies are approved under TSO-C53a Typetube which is compatible with virtually all fluids A (unsleeved) and Type C (firesleeved).

10 * aeroquip 601 hose is also approvedforthese applications. Please contactAeroquip for 601 hose assembly part numbers with9 _ crashworthy numbering system makes it easy foryou to order crashworthy AE701 hose assemblies with370 flared, UNJF aind s(i enge e ow assel m{bles / sw$ veD flired1 t(owash0wo)rthy swivel fDaired ordertoproperlyspecifythe correct hose assembly with "hose assembly sealing" crashworthy fittingsyou need, please use the numbering system shown. on one end and "little gem" AN swivel fittings onStraight and single elbow assemblies are identified the other. The next page shows "accessory sealing"by the number on this page beginning with AE701. hose assemblies. Assemblies may be ordered eitherPart numbers shown on this page are for assemblies with or without 31XK K 0184 0 Base Number for all straight Assembly length in inches;and single elbow assemblies always four digits, last digitindicates fractional length in1/8's of an CodeHose Dash Size | -6 | -8 1-10 -12|Letter Code G H J | K|0 Hiose AssembDy SeafingWithAssembly AE102 Fitting Configurations Unsleeved Firesleeve____.)}