US aviation regulators want the industry to pay closer attention to aircraft wiring that could pose risks for electrical failure and fire, especially on older planes.
The Federal Aviation Administration last week proposed new maintenance, inspection and design standards that would require airlines and manufacturers to analyze aircraft wiring with the aim of making it more fire resistant and easier to pinpoint and correct problems.
Although aircraft design standards are rigorous, wiring is generally considered part of the components they power, like engines or cockpit controls. Maintenance inspections have never given wiring special attention as a separate system.
Current inspection requirements are too general and there is too little attention paid to the impact of how wiring modifications on one part of a plane might affect other parts of the same aircraft, the FAA said.
The new regulation, if adopted, would allow airlines to do more work on wiring at fewer intervals.
"There will be more efficient planning of maintenance programs and less down time for aircraft," said FAA spokesman Hank Price. "Instead of doing it (piecemeal) everyone will come under one umbrella."
The agency estimated the cost of the new program at USD$474 million over 25 years. But it said airlines should save nearly USD$800 million from retooled maintenance procedures and improved safety.
Between 1995-2002, there were nearly 400 aircraft wiring failures, the FAA said. Loose, chafed and broken wires account for roughly 84 percent of all wiring problems.
Damaged wiring can be a fire hazard, while engine oil, hydraulic fluids, galley spills and bathroom fluids can coat wire bundles, making them grimy and attracting dust.
Wiring prompted fresh concern after the 1996 TWA Flight 800 explosion. Investigators believe sparks triggered by a wiring failure ignited vapors in the jumbo jet's center fuel tank. The plane broke apart over the Atlantic off New York, killing all 230 passengers and crew.
Two years later, Swissair Flight 111 crashed off Nova Scotia due to a fire. While investigators never determined an exact cause, suspicion centered on an electric cable.
The disasters spawned safety initiatives, including fuel tank modifications. But post-crash analyses revealed wiring problems may not always be tied to age. They can also be linked to installation and maintenance shortcomings.
