Canadian investigators to release final report on 1998 Swissair tragedy
Tue Mar 25, 9:44 AM ET

MONTREAL (AFP) - Four and a half years after Swissair Flight 111 plunged into the ocean off the shores of Nova Scotia, killing 229 people, Canadian investigators will publish their final report on the accident Thursday, but its exact cause may never be known.



In a statement last week, the Transportation Safety Board of Canada (TSB) said it will publish a report on the "causes and contributing factors of the occurrence."

The MD-11 airplane of Switzerland's now-bankrupt former national airline Swissair had left New York's John F. Kennedy airport on September 2, 1998 in the evening for Geneva.

It disappeared off radar screens 75 minutes later after the crew had signaled there was smoke in the cockpit and asked to make an emergency landing in Halifax, Nova Scotia.

Investigators quickly established that a fire broke out in the cockpit ceiling and then all power cut out just minutes before the tragedy.

Plunging from 3,000 meters high, the MD-11 burst into pieces with debris scattering across dozens of square kilometers and falling as deep as 60 meters into the Atlantic Ocean.

Even though investigators managed to recover the plane's so-called black boxes, they were void of any recording in the last six minutes of the disastrous flight.

For 15 months, divers searched the waters south of Halifax, and managed to recover two million pieces of debris -- some 98 percent of the total weight of the plane. They started trying to reconstruct it in a nearby hangar.

From the start of the investigation, the recovery of charred electrical wires pointed to a fire developing in the cockpit before moving to the back of the plane.

Investigators then quickly narrowed down their suspicions to some traces of electrical short-circuits found on the 21 charred wires, seven of which fed an individual video game system installed in the plane. Swissair was one of the first airlines to carry such systems.

Less than one month after the accident, US aviation authorities concluded that the interrupter system of these video games was incompatible with the MD-11 because it limited the ability of the crew to respond to emergency situations, like in the event of smoke or fire.

This video game system, In-Flight Entertainment Network System/IFENS, was quickly prohibited on all US airplanes, while Swissair withdrew them from its planes as a precautionary measure.

Several independent aeronautical experts, cited by Canadian media, are expecting that these video game consoles will be cited by investigators in the final report, even if the TSB never confirmed that they could have caused the tragedy.

Investigators also revealed several gaps in the norms of inflammability of some material, notably the Kapton sheathing used to isolate a good part of some 250 kilometers of the electrical current in the plane.

They also analyzed the circuitry of the cockpit, but never could determine if the short-circuits had been the cause or a result of the fire, as had been told to AFP by the TSB spokesman Jacques Babin in the first months of the investigation.

They also found that isolating thermal material placed under the fuselage to protect it against extreme temperatures, commonly known as Mylar, had contributed to the spread of the fire.

Some 15 security recommendations were released by the investigators during the course of their work, which has cost more than 50 million dollars (34 million US).

http://story.news.yahoo.com/news?tmpl=story&u=/afp/20030325/wl_canada_afp/canada_swiss_plane_1