KAREN WALKER / WASHINGTON DC
Report says crew were unaware of severity of fire
Use of flammable materials in the wiring and fuselage insulation of the Swissair Boeing MD-11 that crashed in September 1998, killing all 229 people on board, was the main factor contributing to the accident, investigators concluded last week.
Releasing its final report on 27 March, the Transportation Safety Board (TSB) of Canada said the catastrophic fire in the cockpit ceiling area that brought the aircraft down off the Nova Scotia coast was sparked by electrical arcing in wires. Because of fumes the pilots knew there was a fire, but there was no fire detection system on the aircraft to inform the pilots of its precise location - another key issue raised by the crash investigation - until the fire had progressively rendered the flight systems useless.
Included in the final report are nine additional safety recommendations on top of the 14 previously issued. These focus on testing and flammability standards for insulation materials used on aircraft; more stringent certification processes for aircraft supplemental systems; and improvements to flight data capturing systems.
Investigators know the fire was most likely started by an arc from a wire - possibly serving the in-flight entertainment system - located above the cockpit ceiling panels on the MD-11's right-hand side. They stress, however, that circuit breakers, located in a panel above the pilot's heads, were not capable of preventing this type of arcing, and that fire only took hold so rapidly because the insulating materials were so flammable.
TSB crash investigator-in-charge Vic Gerden, calling the crash "a wake-up call", says it was a surprise to discover in tests how easily the insulating material caught fire. The TSB's tests used electrical arcing and match flames which easily ignited the material. "We have learned a lot about the flammability of materials going into aircraft," says Gerden, who adds: "A number of [factors] that induced fire have been eliminated on MD-11s. Have we eliminated the possibility of an in-flight fire? No. But we have come a long way."
Flight International will analyse the report in detail next week.ADDITIONAL REPORTING BY DAVID LEARMOUNT IN LONDON
Source: Flight International
