As investigators of the recent Swissair 111 crash focus on evidence of an electrical fire, the Federal Aviation Administration is preparing to order the inspection and replacement of wiring that could cause fires in aging airplanes. While the inspections will focus on the older planes, many aviation safety experts say the FAA's plan won't alleviate their concerns over wiring used in newer planes flying today. When the wire is subjected to chafing, vibration, and moisture, the insulator may crack, allowing the current to jump to other wires in the bundle, which become fuel for a fire. The Navy and Air Force no longer use Kapton as a primary wire insulator. The FAA refused comment on Kapton, but it has said in the past that arc tracking has not been a problem on commercial aircraft.
Wiring is made to last the anticipated life of a plane.
But about 2,500 commercial planes in the United States are flying beyond their original design life.