April 1, 2005

US regulators proposed on Friday that airlines replace or modify insulation on 1,600 Boeing planes worldwide because the material does not meet fire-proofing standards.

Half the planes covered by the Federal Aviation Administration airworthiness directive are flown by domestic passenger and cargo

airlines. International aviation authorities usually adopt FAA directives.

The plan would require changes over six years on 727 and older model 737, 747, 757 and 767 aircraft. The government's cost estimate ranges from USD$200 million to USD$330 million, depending on whether the material is removed and replaced or simply treated with a chemical fire retardant spray proposed by Boeing.

Cash-strapped airlines are choosing more frequently to remove older aircraft with expensive maintenance requirements rather than keep them in service. It is unclear how many of the affected planes, especially those owned by US airlines, will even be flying several years from now.

"Some very hard business decisions will have to be made," said John Hickey, the FAA's director of aircraft certification. "This will not be an easy task," he added.

The AN-26 fire-retardant coating on the fiberglass insulation blankets, manufactured and installed between 1981 and 1988, do not meet updated fire-proofing standards, the FAA and Boeing said.

Insulation blankets are placed between the exterior aircraft wall and the interior of the fuselage skin to dampen noise and improve climate control.

Some of the insulation, in this case, is placed behind wires and hard-to-access control panels throughout the plane. The FAA recommends work be completed during scheduled maintenance overhauls.

The latest directive is different from an FAA order in 2000 that required the replacement of insulation coated with metalized Mylar on more than 600 US planes made by McDonnell Douglas, which was bought by Boeing in 1997.

But the 2000 order and the proposal on Friday grew out of closer attention to aircraft insulation after a Swissair crash off Nova Scotia in 1998 that killed 229 people. Investigators believe insulation helped spread an electrical fire that brought down the MD-11.Hickey said the new proposal stemmed from extensive tests and reports of in-flight and ground fires on some Boeing planes. Evidence of fire spread through insulation was discovered in some cases only during routine maintenance.

There were no problems with other types of insulation examined, Hickey said.

Hickey and Boeing said it would take about a year to determine if the spray sealant would be an effective alternative.

"As far as we are concerned, we have tested it and it is our recommended solution. It reduces costs and also is effective in preventing aging and contamination, which affects the fire resistant properties of insulation," said Boeing spokeswoman Liz Verdier.