Electrical fires on planes: An underrated hazard
PARIS - The frequency of smoke and fire aboard aircraft, and the numerous problems found in aircraft wiring during special inspections, will come as a surprise to nearly everyone. On average, almost three flights a day are diverted for inflight smoke problems somewhere in the world, the majority caused by wiring, and your chance of being in one is about one in 10,000.
The report, revised repeatedly over several months, is being presented to the Flight Safety Foundation in an Athens conference next week and is being adopted by the Royal Aeronautical Society.
Among the greatest mistakes made by crews in fighting fires is the common practice of opening cockpit doors and windows to clear smoke in an effort to see better, the report said.
Rather than clearing smoke, opening the cockpit usually makes the fire and smoke worse, the report said. It strongly recommended new training for pilots and flight attendants.
"Once the flight deck door is opened, it is no longer a barrier," said the report, written by John Cox, former head of safety for the U.S. pilots union and now head of his own consulting firm, Safety Operating Systems.
"Unfortunately, opening a flight deck door in a smoke event is not a rare exception," said the report. "This tendency to open a flight deck door shows that crew training does not effectively address the importance of maintaining the smoke barrier."
One of the greatest fire dangers aboard aircraft is wiring, the report said. That danger includes the proliferation of wiring aboard newer aircraft, inadequate and worn insulation, bundling of wires in ways that allow arcing in one wire to damage others, and accumulation of dust and flammable debris in wiring areas. Modern aircraft have more than 500,000 feet, or 150,000 meters, of wire.
"The most frequent source of fire in transport aircraft is electrical," the report said. As part of its investigation of the explosion of Trans World Airlines Flight 800 in 1996 just off the coast of Long Island in New York, the U.S. National Transportation Safety Board inspected wiring aboard 25 aircraft. Only one, a new Boeing 737, had clean wiring areas.
"Many of the airplanes had foreign material - lint, metal shavings, washers, screws, rivets, corrosion prevention compound, paint and pieces of paper - between wires or wiring bundles," the report said. "Wire insulation was damaged or cut by the metal debris. There were cases of the core conductor being exposed. Five of the aircraft showed signs of fire or heat damage in wiring."
Yet wiring is often inaccessible behind aircraft walls. Two-thirds of the 397 wiring failures reported between 1995 and 2002 were in areas where detection of the problems was not possible in advance of the failure, the report said. Another problem is that inferior wiring was once installed in aircraft and is starting to fail prematurely.
Wiring has been at the core of many major crashes for decades.
The report recommends some clear changes in common pilot procedures, some of them taught by airlines. First, keep the doors and cockpit window closed. Pilots need better full-face oxygen masks, a greater supply of oxygen and new, balloon-like devices to ensure that pilots can see their instruments, the report said. Larger fire extinguishers should also be put aboard, it said.
It should be easier for crews to get to wiring to fight fires. Also needed are much better housekeeping in wire bays, better wiring inspection, new electrical protection technology, an increased number of fire sensors throughout the plane and use of infrared detectors to locate hot spots behind walls, the report said.
But the report quoted the U.S. Federal Aviation Administration as saying, there would "continue to be in- flight fires because it is not possible to eliminate all the ignition sources or fuel in remote locations for fires in aircraft."
CD, Thanks so much for posting that! I was just about to and you beat me to the punch! Thanks!
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