Thursday, October 15, 1998 - Page updated at 12:00 AM

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Faa Recommends That Most Airlines Replace Insulation

Seattle Times Staff: Seattle Times News Services

WASHINGTON - The Federal Aviation Administration (FAA) recommended yesterday that the insulation on almost all the world's 12,000 passenger jets be replaced as soon as is practical, because new tests are likely to find that it can catch fire when exposed to high heat.

Some aviation officials estimated the price tag for the switch could total billions of dollars. The recommendation grew out of the investigation of Swissair Flight 111, which crashed off the coast of Nova Scotia last month and killed all 229 people on board.

While the cause of that crash is not known, there are indications that some of the wreckage had been subjected to heat and possibly a fire. The pilots reported smoke in the cockpit before the crash, and "heat-distressed" wreckage from the cockpit has been found.

The retrofit, which the FAA said it will likely make mandatory after new flammability tests and specifications are developed in about six months, affects almost all airliners manufactured by Boeing, Airbus Industrie, McDonnell Douglas and Fokker. The material under scrutiny is not wiring insulation but, rather, looks similar to home insulation and is used for the same purposes: to minimize noise and trap heat.

The action is not expected to disrupt flight schedules, because it would be performed during regular major maintenance periods. According to today's New York Times, replacing the insulation involves stripping out the entire interior of the plane - something airlines usually do every three to five years.

In The Times, an aviation expert estimated the cost at $3 million per airplane to replace the insulation. A cost that high could encourage the early retirement of many older jets.

Aviation-industry officials point out that insulation fires have been extremely rare.

The FAA has known about the potential flammability of jet insulation for at least two years.

In 1996, the Civil Aviation Administration of China strongly recommended new tests after a Chinese Eastern MD-11 fire in Beijing in 1995.

The Times reported that the FAA currently tests insulation by hanging a strip of it like a curtain and sliding a Bunsen burner under it for 12 seconds. The insulation passes the test if not too much of it burns away.

In the 1980s, Boeing developed more stringent tests for its own internal use. The Times said that in Boeing's test, which was eventually adopted by other major manufacturers, a Q-Tip is soaked in alcohol, lighted and folded into a pillowlike piece of insulating blanket. A second burning Q-Tip is pushed against the seam of the blanket, and success or failure is measured by how much insulation burns before the Q-Tips stop burning.

That test led to the company's recommendation last year that the metalized Mylar insulation - still in use on the Swissair MD-11 - be removed from planes manufactured by McDonnell Douglas, which Boeing acquired in 1997. The FAA technical center in Atlantic City also issued a report in September 1997 declaring current testing methods inadequate. According to The Times, the FAA is proposing to develop a third, tougher test.

But FAA headquarters did not consider the matter urgent until after the crash of Swissair Flight 111. Investigators found pieces of metalized Mylar in the wreckage, although no burned pieces have been found. The first major portions of the wreckage were dredged from the ocean floor only recently. Still, investigators are examining whether these insulation blankets may have played a role in the crash.

Investigators found that metalized Mylar had been implicated in at least three major aircraft fires, in China, Italy and Denmark. Although the insulation blankets were not a source of ignition, they erupted into roaring fires when subjected to electrical short circuits. No one was killed in those fires.

Thomas McSweeny, the FAA's associate administrator for regulation and certification, said further tests at the FAA's technical center in Atlantic City proved that most other insulation used in airliners also would almost certainly fail any new flammability tests.

Boeing's metalized Tedlar insulation technically passed the Q-Tip test, but full burn tests conducted at the FAA center in Atlantic City showed Tedlar also would feed a fire under the right circumstances. Airbus' insulation foam "does not perform very well" in the swab test, McSweeny said.

McSweeny said the only clearly acceptable insulation at this point is either Fiberglas or a material known as Curlon. Those two products then are wrapped in a polyimide film, commonly known by its DuPont trade name, Kapton.

Compiled from The Washington Post and information from Seattle Times business reporter Polly Lane.

Copyright (c) 1998 Seattle Times Company, All Rights Reserved.


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