Metalized Mylar -- and all other insulation blanket coverings used by McDonnell Douglas and Boeing -- have been tested and meet the applicable flammability requirements for FAA certification.
At this point, there is no indication that any insulation blankets burned or were the cause of, or a contributor to, the tragic loss of Swissair 111. The Canadian investigators will examine any possible involvement of insulation blankets, along with all other possibilities. Boeing will continue to assist in their investigation.
In 1994, as a result of ground fire incidents involving insulation blankets covered with metallized mylar on MD-80s and MD-11s, McDonnell Douglas concluded that an expanded set of test conditions, beyond those required by the FAA, would better determine the flammability characteristics of insulation blanket materials. The company then superseded metalized Mylar with a non-metalized Mylar in production.
As a result of the previous incidents and the availability of a replacement material, in September 1996 McDonnell Douglas recommended that airplane operators replace blankets made with metalized Mylar blanket covering and tape. The company recommended that this be done at the earliest practical maintenance period.