A rchive Date
[ 21-02-2005 ]
Category
[ International Relations ]
sub-Categoy
[ Canada ]
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[Swissair crew shut down engine before crash
By STEPHEN THORNE-- The Canadian Press
Wednesday, May. 24, 2005
OTTAWA (CP) - Crew aboard Swissair Flight 111 inexplicably shut down the plane's No. 2 engine before crashing into the sea off Nova Scotia nearly two years ago, investigators said Wednesday.
Officials with the Transportation Safety Board of Canada investigating the 1998 crash that killed 229 people made the discovery using a chip from a phonebook-sized data processor salvaged from the ocean floor.
They don't know why pilot Urs Zimmermann or co-pilot Stefan Loew would have shut down the engine, located in the middle of the plane's tail.
"It was shut down manually sometime in between the time the flight recorder stopped and the aircraft crashed," said board spokesman Jim Harris.
"That's a six-minute interlude."
Investigators knew all along the engine was not operating at impact because it was the only one of the jet's three engines in which the turbines were not sheared off.
The other engines, on the undersides of the MD-11's wings, were heavily damaged. Each produces between 55,000 pounds and 60,000 pounds of thrust.
The loss of a single engine aboard the tri-engined jet would not account for the fact the plane went down, said Harris. MD-11s can fly on one engine.
More than a million pieces of the downed aircraft have been found. Evidence suggests a fire may have started in the plane's right-side ceiling, just aft of the cockpit, although the study is not complete.
Pilots aboard Flight 111 en route to Geneva reported smoke in the cockpit about 53 minutes after leaving New York. The plane's electrical systems began failing about 15 minutes later and contact was lost.
Six minutes after that, the jet plummeted into the Atlantic Ocean off Peggy's Cove.
Transmissions before contact was lost with the plane indicate the pilots were going through a checklist designed to trace the smoke source by shutting down each of the plane's three electrical systems, one at a time.
Investigators do not know at what stage Zimmermann and Loew were in the checklist when they crashed but, regardless, the procedure would not have shut down an engine, Harris said.
Investigators made the discovery using a single microchip from a Full Authority Digital Electronic Controller, or FADEC. The computer-type units - one per engine - translate commands from the cockpit, optimizing performance under various conditions.
It has taken investigators and Pratt and Whitney technicians all this time to extract that one piece of information about No. 2 engine. No. 2's FADEC is the only surviving unit that yielded worthwhile information.
"When the information is put into the chip, it is not there with a timeline," said Harris. "So that made it very difficult to try to determine what it was telling us."
Finding out how the fire started remains foremost among the investigators' concerns, he added.
Laboratory scientists are still testing 20 burnt electrical wires to determine whether they arced - short-circuited - before or after the fire started.
 World Fact Book (CIA)]
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