The need for the new inspections became known during an audit of American by a joint team of inspectors from the Federal Aviation Administration and the Fort Worth-based airline, according to a statement from American.

'We are reinspecting the MD-80s to make sure the wiring is installed and secured exactly according to the directive,' American spokesman Tim Wagner said in the statement, which did not describe the function of the wiring.

'We are in the process of completing the inspections on the remaining airplanes and will return them to service on a rolling basis throughout the day,' Mr Wagner said.

About 50 departures each were cancelled at American's hubs at Dallas-Fort Worth and Chicago O'Hare international airports. -- AP