Timeline of Insulation Blanket Fires

Air Safety Week, March 14, 2005

Following is a chronology of incidents involving aircraft insulation blankets. Although incomplete, it demonstrates that the Federal Aviation Administration (FAA) rang the safety bell many years ago. The next tolling of that bell will be another death knell if this much-delayed safety initiative is paroled any longer. The National Transportation Safety Board (NTSB), as parole officer, should reissue its blanket recall.

* Nov. 24, 1993: Smoke and a burning electrical smell seeped into the passenger cabin of Scandinavian Airlines (SAS) Flight 666 (Reg. SE-DIB), as it taxied to a terminal in Copenhagen, Denmark. All 110 passengers scrambled out of the plane safely before a raging fire consumed much of the fuselage. For eight years, the incident wasn't reported in the U.S., although two U.S. agencies involved in aviation safety -- the FAA and the National Transportation Safety Board (NTSB) -- assisted the SAS investigation and were aware of wiring and cabin insulation problems years before the North American accidents. Since those accidents, the FAA has issued a series of safety orders regarding inspections and modifications to wiring and the same type of cabin insulation. The SAS accident, which occurred on a flight from Barcelona, was caused by electrical wire that short-circuited, igniting flammable cabin insulation.

Denmark's Aircraft Accident Investigation Board (AAIB) wrote in its 1996 report that two wires short-circuited on the SAS MD-87. These had been installed between layers of Mylar insulation, which ignited. As part of the investigation, the FAA performed fire tests on materials removed from the jet, according to a 1994 FAA letter in the Danish report. The tests, conducted at FAA facilities in Atlantic City, N.J., showed that Mylar insulation failed the FAA's flammability requirements and could ignite from short-circuited wiring.

Despite those tests, the FAA proposed no regulations to remove Mylar from planes or ban it from new aircraft until after the Swissair crash. In August 1999, the agency ordered airlines to remove Mylar from MD-11 and MD-80 series jets within five years. When asked about the Danish accident report showing that the FAA had tested Mylar many years earlier, FAA spokeswoman Alison Duquette said the agency accelerated Mylar-related research after the Swissair accident. "Based on our new test that we developed, we found that Mylar does not meet an acceptable level of safety," she says.

Peter Thulesen, the head of the Danish accident investigation board, declined to be interviewed or to answer written questions about the type of wiring that short-circuited on the SAS jet. The FAA's letter in the Danish accident report, however, revealed that the wire type was Kapton. Boeing, which acquired McDonnell Douglas after the SAS plane was built, says Kapton is the general-purpose wire type on the MD-87. It is also the type that runs through many Boeing and Airbus jets, including Swissair Flight 111. Short-circuited Kapton wires were found by Canadian investigators in their probe of that accident.

* May 1996: The Aircraft Airworthiness Center of the Civil Aviation Administration of China (CAAC) advises the FAA via letter of a 1995 fire on a Chinese registered MD-11, in which the metallized Mylar insulation blanketing burned. The CAAC report cited the "potential danger" posed by the blanket material.

* September 1997: FAA Technical Center Report DOT/FAA/AR-97/58 finds that metallized Mylar blanketing "was totally consumed" when subjected to the flame from a Q-tip soaked in alcohol, concluding darkly that the metallized Mylar film "could propagate a fire in a realistic situation."

* October 1997: Douglas Aircraft issues Service Bulletins encouraging operators to replace metallized Mylar blanketing on DC-8, DC-9, DC-10, MD-11 and MD-80/90 aircraft.

* September 1998: Swissair Flight 111 crashes. The accident airplane is an MD-11 with metallized Mylar thermal acoustic blanketing installed throughout.

* October 1998: FAA Administrator Jane Garvey announces that fire test standards for thermal acoustic blanketing will be upgraded in a "fast track" development effort over the next six months at the FAA Technical Center. This effort was announced as part of an FAA program to remove metallized Mylar thermal acoustic insulation blanketing from an estimated 1,200 aircraft (700 in U.S. registry). The administrator assured that blankets with polyimide (Kapton) covering film and Curlon filler would be "grandfathered."

* January 1999: FAA and the industry begin a series of discussions on potential flammability tests; these discussions continue through June.

* April 1999: FAA misses six-month deadline for new burn test of insulation blankets. On April 6, the FAA issues an emergency airworthiness directive in the wake of a below-deck arcing event on an MD-11 that burned the metallized Mylar insulation blanketing. Operators of 62 MD-11's are ordered to inspect and repair the applicable wire bundles. The case provides a vivid illustration of the type of arcing that can burn insulation.