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There are 179 MD-11s currently in service, 119 of which are dedicated to passenger travel. The jet, a descendant of the DC-10, has technology that allows it to be steered during an emergency by alternating thrust on the two underwing engines even if the center engine in the tail explodes and severs all hydraulic control lines for the rudders and elevators--as in the case of a DC-10 that crash-landed in an Iowa cornfield in 1989. The Swissair MD-11 successfully underwent a thorough inspection just over a year ago, and Swissair's safety-and-maintenance record is solid. But did this model have a history of wiring problems? Since 1992, the FAA has issued a number of airworthiness directives expressing concerns with the electrical systems of MD-11s. Though A.D.s are not necessarily unusual--the FAA issues 400 a year for problems of varying degrees of urgency--several of those issued on the MD-11 refer to potential fire hazards. A 1996 advisory mandated the installation of an extra control-cable guard in response to "reports of burnt electrical wire cable in the cabin attendant console that was caused by the chafing of the wire cables." Another, in 1997, sought to correct "chafing of wire bundles" that could cause smoke in the cockpit.
"An airplane always telegraphs its intention to crash years before it actually does. If I'm right, this one did too," says Arthur Wolk, an aviation attorney who represents plaintiffs in airline crashes. "There have been fleetwide problems in wiring. If I were an investigator, I'd be looking for fire in the wiring bundle, which spread to the cockpit or to a critical flight control." Such speculation is perhaps inspired by the conclusion of the investigation into the crash of TWA 800 near Long Island on July 17, 1996. That disaster's likely cause: exhaust heat from the Boeing 747's air conditioners transformed its fuel into a hot vapor so combustible that a mere spark, possibly from a frayed wire, touched off the disaster.
Then there is the ValuJet theory. On May 11, 1996, spare oxygen-generating canisters stowed as freight aboard ValuJet Flight 592 ignited and sent the DC-9 plunging into the Everglades. The generators had been mistakenly marked empty, and the crew never knew that the plane was carrying hazardous material. Could similar undeclared baggage have doomed Swissair 111? In 1990, air personnel discovered undeclared hazardous cargo--usually because it leaked or emitted a smell--on 63 occasions; by last year, that number had ballooned to 349. Shippers are still not required to disclose to air carriers the contents of their parcels--not even if they contain hazardous materials.