“Safety concerns about wiring systems in airplanes were brought to the forefront of public attention by a midair explosion in 1996 involving a 747 airplane. Ignition of flammable vapors in the fuel tank was the probable cause of that fatal accident, and the most likely source was a wiring failure that allowed a spark to enter the fuel tank. All 230 people aboard the airplane were killed. Two years later, an MD–11 airplane crashed into the Atlantic Ocean, killing all 229 people aboard. Although an exact cause could not be determined, the presence of re-solidified copper on a portion of a wire of the in-flight entertainment system cable indicated that wire arcing had occurred in the area where the fire most likely originated.
Investigations of those accidents and later examinations of other airplanes showed a collection of common problems. Deteriorated wiring, corrosion, improper wire installation and repairs, and contamination of wire bundles with metal shavings, dust, and fluids (which would provide fuel for fire) were common conditions in representative examples of the ‘‘aging fleet of transport airplanes.’’ "〔() FAA Regulations on the certification and maintenance of aircraft wiring systems〕