Jet's Cockpit Suffered Heat Damage
By Don Phillips
A refined transcript of conversations between the pilots and air traffic controllers also shows that the crew was going through an emergency checklist for smoke coming from an air conditioner. But the fragment of conversation that the crew accidentally keyed into air traffic radio does not indicate by itself that there was an air conditioning problem, investigators said, only that the crew was checking for one.
The McDonnell Douglas MD-11 crashed six miles off the southern coast of Nova Scotia last Wednesday night, killing all 229 people aboard.
The new investigative data from the plane's recovered flight data recorder and radio transcript, while preliminary and inconclusive, indicate that either severe electrical problems or a fire -- or both -- affected the aircraft as it descended toward a hoped-for emergency landing at Halifax International Airport.
Investigative sources noted that the flight data recorder and the plane's radar transponder stopped working at about the same time, five to six minutes before the crash. The transponder, which reports altitude and identification information to air traffic radar, is tied to two of the plane's three electrical systems, indicating the possibility of a massive electrical failure. If there was such a failure, it is not clear what caused it.
The data also continue to indicate that the crew was working professionally through an emergency that the pilots apparently thought they could handle up until the moment when all contact with air traffic controllers abruptly ended.
The refined and expanded transcript shows that even though controllers had given the crew permission to descend to 3,000 feet, the pilots chose to level off at 10,000 feet to allow flight attendants time to prepare passengers for an emergency landing. About 90 seconds after leveling off, the crew declared an emergency and 44 seconds later made a last, unintelligible radio transmission. The plane then made a five- to six-minute circling right turn before crashing into the ocean.
Vic Gerden, the investigator in charge for the Transportation Safety Board of Canada, again expressed confidence that Swissair 111 will not join the world's list of mystery crashes. Compared to other recent crashes, such as that of TWA Flight 800, which fell into the Atlantic off the coast of Long Island after exploding in midair, and USAir Flight 427, which plunged to the ground near Pittsburgh, there are more clues in this investigation.
Among those clues were the first signs of fire or heat near the pilots. Gerden said that only a few small pieces of the cockpit had been found but that some of them show "heat stress." He refused to elaborate.
Gerden also said that the flight-data recorder plucked from the ocean floor Sunday shows "numerous irregularities" in the jumbo jet's systems that grew worse as it descended from 33,000 feet to 10,000 feet.
Gerden repeatedly refused to say what systems might have been affected. He said he wanted to avoid giving out partial and unconfirmed information that could lead reporters to draw "little conclusions about little areas."
However, other investigative sources said it will take some time for technicians to determine exactly what systems were affected. The modern solid-state recorder contains a wealth of data, but it also creates a wealth of headaches as technicians try to read the digital information and interpret it, one source said.
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