10 Years After Flight 800, Just Hot Air

sum of two units federal agencies disagree over the ne to eliminate vapors from all airliner firing tanks; it may take a novel tragedy to prove the necessity.

by means of David Evans

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

It wasn't a white horse in fuel use, but a false reading caused by dint of a surge in electricity.

Les than sum of two units minutes later the plane blew up killing all 230 passengers and ship's company members. The National Transportation Safety Board (NTSB) conclud that flammable vapors in the center material for burning tank under the passenger embellish exploded, tearing the airplane apart. Electrical arcing in a wire package outside the tank, which contained the circuit for the No. 4 engine combustible matter flow, caused a power breaker 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 urgencyed was an ignition source -- a match, as it were -- to trigger an explosion. What Kevorkian saw upon 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 material tank safety. "The most prominent issues raised by the agency of the TWA 800 accident touch 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 interrupt ignition sources in fuel tanks. on the other hand the FAA has single issued a proposed requirement to stop 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 have a title to devices by only proposing -- not however requiring -- inspections of aircraft wiring.

upon its new B787, Boeing is installing an inerting a whole 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 thus the weight and complexity of an inerting a whole is not necessary.

Thus, we approach to one of the vexed questions the FAA has created for itself. The agency has adviseed that inerting systems are urgencyed only for center tanks with nearby heat sources (such as air-conditioning packs, which warmed the combustibles vapors on TWA 800) on the contrary 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 turf maintenance, seemed to supporting cushion the NTSB position. In a July 20 alphabetic character 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-question motor wires had melted end aluminum conduit, exposing the combustibles 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 by dint of 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 combination of parts to form a whole The airplane crashed, but it did not be in eruption into a fuel-fed fireball. flat though the crew was soaked in jet combustibles all 17 aboard were able to escape the wreckage.

The aviation industry has answered that its recent efforts to eliminate ignition sources are sufficient to render certain safety, although the Transmile incident allude tos otherwise. The U.S. industry remains flatly oppos to a expensive program to retrofit the existing armada with inerting systems, and the Europeans are oppos to requiring of that kind systems on new planes of that kind as the A380. The vexed question 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 upon the scale of TWA 800 to re-energize the effort to make material for burning tanks truly safe through inerting.