|Origin of fatal Swissair fire continues
to baffle investigators two years later
Pinpointing the origin of the fire aboard Swissair Flight 111, which crashed into the sea near Peggys Cove, N.S., killing all 229 people on board, may prove impossible, Canadian crash investigators acknowledge.
After spending $50-million and two years of painstaking effort, including salvaging nearly two million pieces of the shattered MD-11 from the sea bottom, Canadian Transportation Safety Board investigators have failed to find the cause of the fire.
"Finding the origin of the fire is only one aspect of this investigation," said Vic Gerden, who heads the TSB team conducting the largest and most expensive probe in Canadian history. In an interview, Mr. Gerden said the origin -- perhaps an arcing wire, perhaps something else -- "could be the size of a fingernail."
The board released one of its periodic status reports yesterday, just four days before the second anniversary of the crash on Sept. 2, 1998. In the report, investigators say they are still attempting to find a way to "distinguish between arced wires" to determine if one of them was the origin of the fire, or whether they shorted only after fire burned through their insulation. But it "will be difficult to be conclusive without finding the piece" that caused the fire, Mr. Gerden said.
Although he remained hopeful that the initial event will be found, Mr. Gerden insisted the probe has already contributed to air safety by identifying safety-related problems and urging regulatory authorities to order that they be rectified.
"Safety issues are really the area of this investigation that will be most beneficial," Mr. Gerden said.
The Swissair probe has already produced recommendations calling for inspections of MD-11 wiring, separate power supplies for the cockpit voice and flight data recorders aboard commercial jets, and, most important, for the metallized covering on acoustic insulation blankets, widely used in modern aircraft, to be replaced by less flammable material.
The acoustic insulation in the cockpit ceiling of Swissair 111 burned, contributing to the smoke and helping propagate the fire, although there is no evidence to indicate the fire originated in the insulation.
Mr. Gerden said he expects the field phases of the investigation to be completed this fall. Parts of the shattered aircraft have been reconstructed in a navy hangar near Halifax and investigators are also attempting to use computer modelling to determine the spread of the fire.
The final report, which will include an examination of pilot performance and other "human factors," isn't expected until next year.
The Swissair pilots, who first noticed a burning odour more than 20 minutes before the crash, waited 3½ minutes before alerting air-traffic control. Halifax's longest runway was almost directly in front of them but they initially elected to divert to Boston, where Swissair has a ground staff, even though it is much further away.
Then, after accepting an air-traffic controller's suggestion that they head for Halifax, they rejected a straight-in approach, opting instead to circle out to sea to dump fuel. As the fire worsened, various electrical systems failed and radio contact was lost during the plane's last six minutes of flight.
Evidence from crash probe suggests jet
may have been flyable despite fire
Two years after Swissair 111 crashed into the Atlantic Ocean off Peggys Cove, N.S., evidence emerging from the investigation indicates the plane may still have been flyable despite an electrical fire but that pilots may have lost control in the dark.
Additionally, detailed simulations of the critical minutes after smoke was first detected in Flight 111's cockpit show that the pilots might have been able to land the big MD-11 at Halifax airport if they had understood how dire the situation was and had made an immediate emergency descent.
Instead, the pilots chose to turn away, believing the aircraft was too heavy to land unless fuel was dumped over the Atlantic. At the end, the pilots may have become disoriented when even their backup instruments failed as they struggled to keep the aircraft aloft while coping with smoke from a fire in the cockpit ceiling.
Vic Gerden, the Canadian investigator in charge of the still-unfinished, $50-million probe into the crash that killed 229 people two years ago today, says he does not know about any landing simulations.
But he acknowledged that airlines all over the world revised their procedures after the Swissair disaster to make rapid landing an urgent priority. In an interview, Mr. Gerden -- lead investigator for the Canadian Transportation Safety Board -- also confirmed that his team has "found nothing that would clearly show [the aircraft] was unflyable."
Wreckage recovered from the sea bottom indicates the plane's engines were working (although the pilots possibly shut one down as part of the smoke&fire checklist) and that its flight controls were functioning [as well] at the time of impact.
Complete electrical failure is suspected -- nothing was heard from Swissair 111 during its last 6½ minutes as it flew an irregular clockwise circle over Mahone Bay -- but modern jetliners are designed to fly even if all three electrical systems fail.
"I think there was a loss of control at the end," said Ken Adams, the senior safety officer for the Air Line Pilots Association and that organization's representative on the Canadian investigation. The ALPA is the pilots union representing more than 53,000 pilots at 50 U.S. and Canadian airlines.
Mr. Adams, a veteran pilot who flies MD-11s for Delta Airlines, said pilots have been fighting for years to get airlines and manufacturers to change their operating procedures to focus on the need for urgency in dealing with smoke in the cockpit.
"I think there was a general complacency in the industry [before the Swissair disaster]," he said.
"Its not always easy to [make pilots] understand that 'get your ass on the ground' means 'get your ass on the ground now.' "
Many airlines -- including Swissair -- have revised their procedures regarding smoke since the accident. Fire on board aircraft has long been known to be terribly dangerous and a review of accidents regarding fatalities involving fire on board has shown that crews rarely have more than 15 or 20 minutes to get the aircraft on the ground. Still, the Swissair crash has been a "catalyst for change," said Jim Harris, spokesman for the safety board.
"If there is smoke, find a place to land and get it down," is how Mr. Harris describes the new approach.
Pilots have taken heed.
In the United States, one commercial jet crew now makes a request every day on average to divert and land at the nearest airport because of smoke. That represents only a tiny fraction of the thousands of daily flights, and most such incidents turn out not to be serious. But the attitude of "land now, troubleshoot later" appears to stand in stark contrast to the Swissair procedures followed by the crew of Flight 111.
The two pilots initially said they wanted to go to Boston, 500 kilometres behind them, and only changed course to nearby Halifax at the suggestion of an air traffic controller. They also initially assessed the situation as undeserving of a declaration of an emergency, radioing only "Pan, pan, pan," which is indicative of a less serious problem.
Minutes later, lined up with Halifax's longest runway, they elected to turn away, while the flight attendants finished clearing dinner. And then they asked to turn out over the Atlantic to dump fuel to lighten the aircraft.
Although Swissair describes landing an aircraft above its recommended landing weight as "extremely risky," Boeing says all its aircraft -- including the MD-11 -- are certified to land overweight and need not even be inspected for damage if the touchdown is smooth.
Nor does Canadian law prohibit the emergency dumping of fuel over land -- even over populated areas. However, both the pilots of Flight 111 and the air traffic controller seemed to want to wait until the MD-11 headed back out to sea before dumping.
Boeing spokeswoman Loretta Gunter said yesterday that there is no operational reason "not to dump during descent."
Even if Swissair 111 suffered a complete electrical failure after turning away from Halifax, a rudimentary set of mechanical and battery-powered instruments -- such as an altitude gauge (altimeter), a speed indicator and an artificial horizon -- should have provided the pilots with the information they needed to fly the aircraft.
However, a source close to the investigation says evidence indicates the battery-powered artificial horizon may have failed on Flight 111, leaving the pilots disoriented in the dark over the ocean, and possibly coping with thick smoke and heat.
Simply put, the pilots may have been fed a false sense of what was level because the gyroscope powering the artificial horizon may have slowed.
Disorientation in the dark is a common cause of crashes involving pilots unqualified or inexperienced in flying on instruments -- it was the cause of the crash that killed John F. Kennedy, Jr. last year. But even the most experienced pilot can easily become disoriented in the dark without an artificial horizon.
In clear skies, the Swissair crew likely could have seen the real horizon, even at night. But Mahone Bay was under patchy overcast skies when the crash occurred. Near Halifax airport, the skies were clear.
Swissair said immediately after the disaster that it would have been impossible to land at Halifax because the aircraft was too high and too heavy.
But using actual flight data gathered during the investigation, MD-11 pilots in simulators have repeatedly landed safely after an emergency descent to Halifax.
According to a source familiar with the simulations flown by a number of Delta pilots, they had no difficulty getting the aircraft down from its original cruising height of 33,000 in either the time or distance available to the Swissair crew.
Since Flight 111 was over Boeing's recommended landing weight, the length of runway required to stop safely would have been greater than usual. But Halifax's runway 06 is more than long enough to land an MD-11 weighing 253 tonnes, the reported weight of Swissair 111 without dumping fuel.
The simulations involved direct approaches to runway 06 after emergency descents and a slightly longer routing in which the aircraft overshot Halifax airport, made a tight turn and landed from the other direction on the same runway.
In the simulator, pilots put the plane on the ground in times ranging from 14 to 16 minutes.
The simulations -- and Delta's more urgent operating procedures even before the Swissair crash -- will likely become part of the pending lawsuits against Swissair.
Delta and Swissair, like many airlines, have so-called code-sharing agreements where they jointly operate routes or agree to carry each other's passengers.
More than 50 of the passengers on the Swissair 111 held Delta tickets. Some may not have realized they were actually flying Swissair until they boarded the plane.
A representative for Swissair was not available for comment on this story.
THE LAST MINUTES OF SWISSAIR FLIGHT 111
1. 10:10:45 (Atlantic Summer time)
Pilots first notice odour and 2 minutes later smoke in the cockpit.
Swissair 111 declares "Pan, Pan, Pan" with a request to
divert to Boston.
Air traffic controller suggests Halifax is closer. Pilots agree.
Non-emergency descent rate of 4,000 ft./min. Swissair 111, now heading
049 degrees is still roughly in line with Halifax's longest runway
(060 degrees) and accepts Halifax's air traffic controller's offer
of "vectors for (runway) six."
Swissair 111 is now 50 kilometres from the runway, pilots elect to
Pilots request a turn out to sea to dump fuel and lighten aircraft.
(No further radio communication comes from the aircraft. It crashes
about 6 minutes and 40 seconds later.)
Unfortunately the simplistic solution of "land ASAP" doesn't work in mid-ocean - so better solutions have to be found