STEPHEN THORNE

NEW YORK (CP) - Aviation's top regulator knew jet insulation blankets could easily catch fire more than two years before they contributed to the deaths of 229 people aboard Swissair Flight 111 off Nova Scotia, documents show.

The U.S. Federal Aviation Administration waited another year before ordering the insulation replaced aboard 1,230 aircraft worldwide and it gave airlines four years to do the job.

"Tests show that metalized mylar (insulation) falls far below the new test standard," the FAA said last August. "It ignites much more easily than other materials and can spread fire because its properties are much different."

Chinese authorities warned the FAA in 1996 of problems with the blankets, designed to keep heat in and noise out, urging the regulator and Boeing Co. to "make prompt and positive response."

The Chinese report came after three aircraft fires in 1994-'95, including one involving an MD-11 like the one that crashed off Peggy's Cove in September 1998.

"The cause of fire during all these incidents was led by (ignition of the) insulation blanket," said a May 24, 1996, report to the FAA from the Civil Aviation Administration of China.

The five-page report, obtained by The Canadian Press, describes tests conducted at the administration's Aircraft Airworthiness Centre in Beijing.

"When we placed a piece of the centre material of the insulation blanket on the ground, and ignited a corner by an igniter, the material was consumed by fire rapidly," said the report.

"It was considered that the film of the insulation blanket was fire flammable and didn't meet the requirements."

The Chinese found the way the blankets were sewn promoted the spread of fire and its location on the airplanes was in some cases dangerous.

In a July 1996 response to the Chinese report, the FAA said it was researching the issue.

"With respect to the tests your agency conducted, we note that the test of the sewn edge of the blanket would not have been required for certification," wrote Ronald Wojnar, manager of the FAA's Transport Airplane Directorate.

"While the tests you conducted are illustrative, they do not invalidate the certification of the material."

The FAA took action after the Transportation Safety Board of Canada recommended use of the blankets be reduced or eliminated based on wreckage from Flight 111.

"There are clear indications that a significant source of the combustible materials that sustained the fire was thermal acoustical insulation blanket material," the safety board said in a 1999 letter to the FAA.

"Burnt remnants of this material, quenched by sea water, were found in the wreckage. It is the board's view that the operation of aircraft outfitted with thermal acoustical insulation blankets incorporating metalized PET cover material constitutes an unnecessary risk."

In a letter to the International Aviation Safety Association, an industry watchdog, FAA associate administrator Tom McSweeny said the regulator did not determine an "unsafe condition" existed until last year.

"The airworthiness directive was not part of our original plans . . . but there was swift action taken as a result of information gained from our test program," McSweeney wrote IASA chair Lyn Romano last month.

Mylar blankets have been identified as a major factor in at least five other aircraft fires. McDonnell Douglas, Boeing-owned makers of the MD-11, told operators they should stop using metalized mylar in 1997.

There was a limited response from airlines, primarily because of the cost - estimated at between $380,000 US and $880,000 US per aircraft.

FAA officials said the agency backed away from a plan to order insulation replacements in almost every U.S. commercial airplane because research showed most existing insulation passes or only narrowly fails new flame tests.

Instead, a more limited order applied to 699 U.S.-registered McDonnell Douglas planes. They include the MD-80, MD-88, MD-90, DC-10 and the MD-11.

There are no MD-11s in Canada and no Canadian-registered aircraft left the factory fitted with the insulation.

Canadian-operated DC-10s were built before metalized mylar came into use between 1987 and 1994, but some may have been retrofitted with the material.

Affected airlines include American, Delta, Continental, Trans World, Alaska, Federal Express, Reno Air, Aeromexico and US Airways.

Swissair has begun retrofits under a followup order from its own authority.

"The work must be accomplished at the earliest maintenance check but no later than four years," said the FAA.

Swiss pilots of Flight 111 from New York to Geneva flight reported smoke in the cockpit and were minutes from Halifax airport when they turned away to dump fuel. They crashed into the Atlantic Ocean near Peggy's Cove.

Investigators found evidence of fire near the wall between the cockpit and forward galley. Faulty electrical wiring is believed to have started the fire.