By Reuters

Philadelphia - Swissair knew wiring aboard its Flight 111 posed a substantial fire hazard at least seven years before the MD-11 aircraft crashed off Nova Scotia, lawyers for crash victims' families said Tuesday.

In a 23-page summary of "facts, theories and contentions," filed in U.S. District Court, a committee of plaintiffs' lawyers said a fire sparked by general wiring probably was the cause of the Sept. 2, 1998, crash that killed all 229 people on the New York City-Geneva flight.

The Swissair crew reported smoke in the cabin minutes before the plane plunged into the Atlantic off Peggys Cove.

Canadian crash investigators found 13 wires coated with a material called aromatic polyimide insulation that showed evidence of superheating.

The documents said both the wire coating, sold under the brand name Kapton, and the aircraft's blanket insulation material, known as metalized Mylar, were known safety hazards when Swissair bought the plane from McDonnell Douglas in 1991. Kapton and Mylar are made by DuPont Co.

"Prior to and during 1991, Swissair had actual knowledge that the Kapton insulation used to insulate certain electrical wire could become degraded and worn in the ordinary course of its use...creating a substantial risk of fire," the plaintiff's summary reads.

Swissair, its code-share partner Delta Air Lines Inc. and Boeing Co., which bought McDonnell Douglas in 1997, are among defendants named in 167 lawsuits seeking $16 billion US in damages for the crash of Swissair Flight 111.

Plaintiffs contend the airline and the plane's manufacturer knew the wires and blanket insulation posed a special hazard when placed near each other.

The list of defendants include Swissair's parent, SAirGroup, and SR Technics AG, an SAirGroup subsidiary, as well as Interactive Flight Technologies Inc., which provided the entertainment system investigators believe may have been implicated in the fire.

In a separate lawsuit, plaintiffs are suing DuPont Co. for $3.8 billion for its role as manufacturer of the insulation material.

The summary document was filed at the behest of Judge James Giles, who will use the allegations it contains to gauge how far plaintiffs can go to uncover actual evidence of culpability as a so-called discovery phase begins. Lawyers for Swissair and its fellow defendants were not immediately available to comment on the filing.

The documents suggest Swissair Flight 111's crew may have helped the fire spread by following McDonnell Douglas/Boeing procedures that call for circuits to be turned on and off. The action may have channelled more electrical energy through faulty Kapton-coated wires.

The dangers of Kapton-coated wires were known as early as 1980 to U.S. military authorities who banned their use in warplanes later that decade. Trans World Airlines complained about the wiring to Boeing in 1977, blaming it for fires dating to 1972.

The documents said McDonnell Douglas knew about the military ban but continued to use Kapton wires on commercial jets including the MD-11.

The documents said the aircraft-maker knew of fires that occurred from 1993 to 1995 aboard aircraft in Denmark, China and Italy in which metalized Mylar was shown to have sustained and spread flames.