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Canadian, Swiss and U.S. specialists are scouring the waters south of Nova Scotia for clues to the problem that fed smoke into the cockpit of a Swissair Boeing MD-11 and led to its crash there last week.


Joined in Halifax late last week by officials from Swissair, the U.S. FAA, Boeing and Pratt & Whitney, investigators for Canada's Transportation Safety Board began organizing their probe of the Sept. 2 crash of Swissair Flight 111, which killed all 215 passengers and 14 crewmembers. It was the first of a passenger MD-11. At Canada's invitation, the U.S. National Transportation Safety Board sent a six-member team to aid in the probe.


In addition to searching for Flight 111's cockpit voice and flight data recorders, the investigators worked on identifying what could have caused smoke to enter the cockpit.


Among the possible smoke sources investigators were reviewing last week were shorting or burning of wire bundles in the cockpit or the avionics bay below, an electrical component malfunction in or around the cockpit or decomposition of a hazardous-materials shipment on the aircraft.


Aging wiring is not a likely culprit, since the accident aircraft was delivered to Swissair just seven years ago. The accident aircraft, registry HB-IWF, had accumulated more than 6,400 cycles and more than 35,000 flight hours at the time of the crash. Swissair officials said it last underwent major maintenance a year ago. One senior Swissair official said the aircraft had been in "perfect working order."


As investigators worked on a fault tree that could uncover the source of the smoke, divers from the Royal Canadian Mounted Police (RCMP) late last week began searching in the 100-ft.-deep Atlantic waters for the cockpit voice and flight data recorders and what was believed to be an intact, submerged section of Flight 111's tail.


The flight data recorder could prove a boon to investigators if it is like most on MD-11s and captured close to 200 performance parameters. That much data would allow them to precisely recreate Flight 111's final moments, which could lead investigators to decide not to retrieve most of the aircraft's debris from the ocean.


Inadequate FDR data was among the factors that led U.S. investigators to perform extensive recovery operations in their search for the causes of two other accidents whose wreckage ended up underwater--the 1996 crashes of ValuJet Flight 592 and Trans World Airlines Flight 800.


The Swissair accident had similarities to both of those crashes. Like TWA 800, the MD-11 appeared to have plunged suddenly into the ocean, wiping out any chance of survival for its occupants and heralding a long, difficult and costly investigation. And just as in ValuJet 592, the accident sequence appears to have begun with a two-pilot crew struggling to overcome potentially disabling fumes and land their aircraft safely.


Flight 111 took off from New York's John F. Kennedy International Airport on time at 7:50 p.m. EDT Sept. 2 for a planned 6 hr. 40 min. flight to Geneva, continuing to Zurich. About 90 min. later, however, the aircraft encountered a problem.


According to Roy Bears, an investigator for Canada's Transportation Safety Board, the Swissair pilots at 9:14 p.m. EDT made the "Pan-Pan-Pan" international urgency call, informing an air traffic controller in Moncton, New Brunswick, that they had smoke in the cockpit. The Moncton Center oversees all flights in Canada's Maritime provinces.


Flight 111 was at 33,000 ft. at that point. The pilots requested a diversion to Boston's Logan International Airport, but the Moncton controller advised them Halifax International Airport was closer. As the MD-11 was guided toward Halifax, Bears said, the crew declared an emergency. There were indications that they intended to dump fuel, he said, although it is unclear whether they did so. It was unclear last week how much communications ensued between the aircraft and ATC.


Air traffic controllers reported that the final secondary radar return put Flight 111 at about 8,000 ft. That was at about 9:30 p.m. EDT. Investigators will want to determine whether primary radar data tracked the aircraft's final descent. The MD-11 crashed into St. Margaret Bay, an inlet dotted with islands about 20 naut. mi. southwest of Halifax.


Residents along the bay's shores reported hearing a jet pass low overhead followed by what was variously described as a heavy thud or a pressure wave. "I wouldn't call it an explosion," said Linda Farmer, a resident of nearby Blandford, Nova Scotia. "It was more like a shock wave."


Scores of rescuers found no large sections of the MD-11 afloat, only shattered debris, and few of the more than 40 bodies recovered as of late last week were intact.


As the accident investigators set about their work, RCMP officials were coordinating with Swiss and U.S. security counterparts to assess whether the crash was the result of a criminal or terrorist act. "There is nothing to indicate any suggestion of a criminal act at this time," a senior RCMP officer said Sept. 3.


While the flag carrier of a politically neutral nation may be an unlikely target for terrorists, Swissair Flight 111 was operated under that airline's longstanding code-sharing and marketing alliance with Delta Air Lines. Delta had sold tickets for 53 seats on the accident aircraft, an official of that Atlanta-based carrier said, and one of the 12 flight attendants on it was a Delta employee.


U.S. airlines and airports were warned to be on alert two weeks ago for attempts at retaliation for the U.S. bombing of alleged terrorist camps in Afghanistan (see p. 166). U.S. officials said the group running the camp, led by Osama bin Laden, were planning imminent attacks against U.S. interests. Bin Laden has been implicated in the bombings of U.S. embassies.


The accident was the first major one for Swissair since Oct. 7, 1979.






Flight 111 crashed short of Halifax. Although it was a launch customer for the MD-11, Swissair had been planning to replace the trijet with Airbus Industrie A340s in a few years.

İMarch 31, 2003 The McGraw-Hill Companies Inc.

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