07-Sep-1998
JAMES T. McKENNA/WASHINGTON |
Photo |
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.
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