Some 830 Boeings built from 1981 to 1988 need fresh or modified insulation to counter newly discovered risk

The US Federal Aviation Administration has proposed a six-year deadline for airlines to remove a newly discovered fire hazard on some 830 US-registered Boeing aircraft. Five aircraft types built between 1981 and 1988 – the 727, 737, 747, 757 and 767 – require new or modified insulation blankets, says the notice of proposed rulemaking (NPRM).

The six-year deadline, which can become effective after a required 60-day public comment period, will give airlines the option of replacing the hazardous insulation blankets during regular heavy maintenance checks, says John Hickey, director of the FAA's aircraft certification service.

The FAA has identified the hazardous material as Orcon Orcofilm AN-26, a water-resistant transparent coating applied to blankets to contain insulation batting. In a series of tests between 2002 and 2004, the coating failed to pass a higher FAA standard for fire-proofing materials that takes effect in September, says Hickey.

The so-called "arc-and-spark" test replicates the effect of two exposed electrical wires coming into contact. Hickey says the FAA considers the new standard a more realistic test for cabin materials than the agency's previous "Bunsen burner" standard, which exposed the material to an open flame. Unsafe materials are now defined as any that are "susceptible to ignition by electrical arc or sparks and that would propagate a fire".

AN-26 is the second material to be banned by the FAA under the new standard. In 2000, it ordered metalised Mylar insulation to be removed from more than 700 McDonnell Douglas aircraft after it failed the arc-and-spark test. This followed the 1998 crash of Swissair flight 111, an MD-11, off the coast of Nova Scotia, Canada after an in-flight fire. Airlines must remove the Mylar by 30 June.


Source: Flight International