Airlines will have four years to replace the metalized Mylar that fails anti-flame tests.
U.S. airlines will have to replace the insulation in nearly 700 airplanes over the next four years because it badly fails an anti-flame test that is being developed, the Federal Aviation Administration said Wednesday.
The airworthiness directive, however, will not require the sweeping insulation replacement that the agency had discussed back in October, shortly after a Swissair plane crashed following a report of smoke in the cockpit.
FAA officials said the agency backed off the plan, which would have ordered the replacement of insulation in nearly every U.S. commercial airplane, because recent research showed that most existing insulation would pass or only narrowly fail the new flame test.
Instead, the more limited order will apply to 699 U.S. airplanes insulated with the questionable product, metalized Mylar. They were built by the former McDonnell Douglas Corp., now owned by the Boeing Co., and include the MD-80, MD-88, MD-90, DC-10 and the MD-11. That is the type of Swissair plane that crashed last September, killing all 229 aboard. The cause of the crash remains under investigation.
Under the proposed order, airlines will have four years to replace metalized Mylar with products that pass the new flame test. The order will take effect after a 45-day comment period and time for revisions.
The carriers primarily affected are American Airlines, Continental, Delta and TWA, although Alaska Airlines, FedEx, Reno Air and US Airways fly some affected planes.
Insulation is used in airplanes to keep passengers warm and to dampen engine noise and the sound of rushing air. It is often installed in sheets. In 1997, McDonnell Douglas told airlines they should consider replacing metalized Mylar because it might be flammable.