Wires that weren't properly secured could chafe or fail, causing a short that could affect power or trigger a fire close to the fuel tanks, according to the airworthiness directive.
An American spokesman said its inspections found no evidence of chafing or rubbing. But the airline found about 80 jets that needed modifications, American spokesman Tim Wagner said. Twenty jets were repaired and returned to service by Wednesday afternoon, he said.
The FAA has sent some inspectors from its office overseeing American Eagle to help complete the audit of American by Friday, FAA officials said. The work is being done in Tulsa, where American performs its heavy maintenance.
"If they need more time and there are issues, we would rather have those issues be addressed thoroughly," said Lynn Tierney, the FAA's assistant administrator for communications.
The FAA scrutiny was touched off by a congressional investigation, managed by Rep. James Oberstar of Minnesota, which found that Southwest Airlines operated 46 jets that missed federally required inspections for fuselage cracks.
Mr. Oberstar, chairman of the House Transportation and Infrastructure Committee, plans to hold an April 3 hearing to examine what he called lapses in FAA oversight. Two Senate subcommittees also plan hearings in April.
The FAA's initial audit will be followed by a check of a much larger sample of airworthiness directives. The deadline for that effort is June 30.
That campaign could detect more problems with the controls that airlines have established to ensure compliance with the directives, experts said. That's because many airlines may incorporate an inspection into a maintenance plan but fail to properly document the work as an airworthiness directive.
In addition, some directives require inspections to be repeated. With airline maintenance occurring in different places across the country, the possibility exists that only part of the work may have been done, experts said.
"It's a substantial piece of work," Mr. Goglia said. "You could very easily miss something, or you could accomplish the work and miss the sign-off."
The audit, which applies to all US carriers, wraps up this week. The FAA could announce results as soon as Monday.
The comprehensive audit could last three months
The FAA has proposed a $24.2 million civil penalty against American Airlines Inc. for failing to correctly follow an AD involving the maintenance of its McDonnell Douglas MD-80 aircraft.
The penalty against American Eagle Airlines is for allegedly operating more than 1,000 flights using airplanes on which improper repairs were performed on landing gear doors.