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View Full Version : Aisle lights suspected in Swissair crash


tva164
7th Aug 2001, 15:48
Possible link to fire: Other wiring on Flight 111 found to be charred


Dean Beeby
The Canadian Press

Stephen Savoia, The Canadian Press

HALIFAX - Another aircraft electrical system has come under suspicion by the team investigating the crash of Swissair Flight 111.

Tests have shown the aircraft's overhead aisle and emergency lights could be linked to the cockpit fire believed to have brought down the MD-11 aircraft on Sept. 2, 1998, near Peggys Cove, N.S. All 229 aboard died.

Ceiling panels recovered from the wreckage show heat discolouration apparently from the 28-volt incandescent bulbs used in the passenger-cabin lighting system.

And test results obtained under the Access to Information Act show temperatures in the aisle light fixtures of three other MD-11 aircraft rose as high as 200C in experiments.

The high temperatures caused the discolouration of ceiling panels as well as some deformation of the lights' plastic coverings.

Tests also showed the aisle light bulbs on MD-11s typically draw electrical current levels 143% higher than they were designed to withstand.

"We haven't eliminated the possibility that an aisle light might have been involved," Larry Vance, an investigator with the Transportation Safety Board of Canada, confirmed in an interview from Hull, Que.

The complex investigation, which is approaching its third anniversary, has also raised doubts about three cockpit map lights. Other MD-11 aircraft have had heat problems with their map lights, which have been ordered deactivated in many of the aircraft.

Only two of the three map lights in the Swissair Flight 111 cockpit have been fully recovered and neither shows evidence of heat damage. Investigators believe they have recovered pieces of the missing third map light, used by the pilot, but they also show no signs of fire, Mr. Vance said.

The aircraft's in-flight entertainment system shows damage to its power-supply wires, raising questions about whether it was the source of fire. And investigators are examining whether the aircraft's general wiring, some of which was found charred with burnt insulation, caused or was merely affected by the fire.

The latest finding is more evidence the MD-11 aircraft was beset by electrical problems -- at least one of which was likely responsible for the tragedy.

The overhead aisle and emergency lights were manufactured by Luminator Aircraft Products, based in Plano, Tex. The firm has provided lights for every Boeing aircraft model since the 1950s, as well as for such McDonnell Douglas aircraft as the MD-11.

A company spokesman said the Transportation Safety Board forwarded its test results for the lights, but the firm's own investigation showed no similar problems.

"We ran our own tests here for weeks, and could not duplicate that," said Bob Presnell, adding no customers have complained and the company has had no previous evidence of problems.

The bulb type could be changed if the board concludes there is a serious problem, Mr. Presnell said from Plano, near Dallas.

No Canadian carriers operate MD-11s, which were built in the United States.

The Swissair investigation showed temperatures in the aisle light fixtures tended to be much higher in the front part of the passenger cabin, in the first-class compartment nearest the cockpit, than in the rear. The team is expected to release a final report next year on the cause of the disaster.