couple federal agencies disagree over the ne to eliminate vapors from all airliner material for burning tanks; it may take a strange tragedy to prove the necessity.

couple federal agencies disagree over the ne to eliminate vapors from all airliner material for burning tanks; it may take a strange tragedy to prove the necessity.

by dint of David Evans

"Look at that crazy firing flow indicator there on No. 4 papal court that?" exclaimed Capt. Ralph Kevorkian. Sitting in the pilot's seat forward TWA Flight 800, a B747 Kevorkian was remarking to associate crew members about a spike in the combustible matter flow reading in the No. 4 engine as the airplane passed between the sides of 13,000 feet after takeoff forward July 17, 1996, from JFK International Airport for an overnight flight to Paris.

It wasn't a wave in fuel use, but a false reading caused by the agency of a surge in electricity.

Les than brace minutes later the plane blew up killing all 230 passengers and horde members. The National Transportation Safety Board (NTSB) conclud that flammable vapors in the center firing tank under the passenger adorn exploded, tearing the airplane apart. Electrical arcing in a wire bundle up outside the tank, which contained the circuit for the No. 4 engine firing flow, caused a power billow that jumped from wire to wire and ultimately to the wires connecting the fuel-quantity indicators in the center tank.

The electric general traveled down these normally harmless wires into the tank and ignited the vapors. All the vapors stand in want ofed was an ignition source -- a match, as it were -- to trigger an explosion. What Kevorkian saw onward the fuel gauge was a spurious reading portending imminent doom.

Now, 10 years after the crash, the NTSB is mightily frustrated with the lack of progres in efforts to improve firing tank safety. "The most prominent issues raised on the TWA 800 accident affair protection against flammable fuel tank vapors and aging electrical systems" the NTSB told the Federal Aviation Administration (FAA) earlier this year.

What has the FAA done to address those issues in the years since the Flight 800 tragedy?

There have been endles and earnest meetings, and various directives have been issued seeking to thwart ignition sources in fuel tanks. on the other hand the FAA has solitary issued a proposed requirement to intercept fuel-tank explosions through an "inerting" proces that fills voids in the tanks with nitrogen-enriched air. It also has left airline manufacturers to their acknowledge devices by only proposing -- not over and above requiring -- inspections of aircraft wiring.

in succession its new B787, Boeing is installing an inerting regularity for both the center section and the wing firing tanks. European manufacturer Airbus has designed the A380 double-decker without a center wing tank and claims it has eliminated all potential sources of ignition from its wing tanks in such a manner the weight and complexity of an inerting body is not necessary.

Thus, we proceed to one of the vexed questions the FAA has created for itself. The agency has give an inkling ofed that inerting systems are wanted only for center tanks with nearby heat sources (such as air-conditioning packs, which warmed the combustibles vapors on TWA 800) nevertheless the NTSB has recommended that flammable vapors be eliminated from all tanks.

The May 4 explosion of a Transmile Airlines B727 at Bangalore, India, in which a wing tank explod as the airplane was being repositioned for landed estate maintenance, seemed to support the NTSB position. In a July 20 verbal expression to the FAA, the NTSB which was supporting a probe through Indian aviation authorities, said investigation of the incident "revealed that the ignition occurr where [fuel] cross-examine motor wires had melted by the agency of aluminum conduit, exposing the firing vapors to potential ignition energy" Although the aircraft had been modified in accordance with an FAA directive to impede the wiring problem, the design change was clearly ineffective. Inerting is necessary, the NTSB said.

The NTSB recommendations appear to be further supported from the April 3 crash of a U Air Force C-5 jet transport at Dover Air Force Base in Delaware. The C-5 has an inerting rule The airplane crashed, but it did not cast forth violently into a fuel-fed fireball. on a level though the crew was soaked in jet firing material all 17 aboard were able to escape the wreckage.

The aviation industry has accorded that its recent efforts to eliminate ignition sources are sufficient to render certain safety, although the Transmile incident put in mind ofs otherwise. The U.S. industry remains flatly oppos to a expensive program to retrofit the existing cove with inerting systems, and the Europeans are oppos to requiring in the same state [i]or[/i] condition systems on new planes in the same state [i]or[/i] condition as the A380. The point to be solved [i]or[/i] settled with the industry's approach is that if reducing ignition sources is not sufficiently effective, inerting would still guard against catastrophic failure. Consider it the belt and suspenders approach to safety.

The Families of the TWA Flight 800 Association have asked: "Can the airline industry and FAA afford another mass los of life similar to this accident?"

Unfortunately, it may take another disaster onward the scale of TWA 800 to re-energize the effort to make firing material tanks truly safe through inerting.