irements are negligible4.2 SAFETY FOAMThe safety foam is a sponge-like material constructed of interconnecting strands (Ott, 1997, p65). In use in land-based aircraft since Vietnam, foams have proved to be an effective protection against such ignition sources as hostile groundfire, lightning, static discharge and electrical shorts.The foam acts like a three-dimensional fire screen and functions in several ways. The foam absorbs heat and removes energy from the combustion process. It mechanically interferes with the compression wave of an explosion, making the vapors lean in the ullage and less vulnerable to explosions.Boeings fuel systems specialists have been negative regarding the use of safety foam in commercial aircraft (McKenna, 1997, p33). Even though the foam has been improved to minimise the weight, the foam carries a weight penalty and, when inserted in fuel cells, limits tank capacity, an important factor in long-range operations. The extra weight of foam that every aircraft must curry would average at 1,200 to 1,400 lb. This extra weight equals as many as eight passengers with baggage. Another problem cited by Pa.-based Foamex International Inc, is the lingering problem with static discharge in cold weather operations.4.3 JET FUEL ALTERNATIVEA representative from the Fuel Systems Safety Program, said (McKenna, 1997, p33), an alternative to increasing fuel system safety is the development of a JP-5 like fuel. Used primarily by the U.S Navy, JP-5 is refined with a higher flammability level and less volatile than that of Jet A, making it safer for use in the hot environment of aircraft.The cost of the JP-5 fuel compared with the cost to the current fuel shows that they are not much different. 4.4 VENTED AIR GAPS and INSULATIONA reduction in the potential for fuel tank explosions could be attained by reducing the heat transfer to fuel tanks from sources such as hot air ducts and air conditioning packs that are now located ...
