Widespread airplane audits called for by the Federal Aviation Administration have prompted both Delta and American Airlines to reinspect hundreds of their planes today.

On Wednesday evening, Delta became the latest carrier to take extra maintenance precautions. Delta announced it expects cancellations because it is reinspecting wiring on 133 of its planes.

The airline said it will contact customers in advance and offer rebooking. It expects to have the issue resolved by the end of the week.

Earlier Wednesday, American Airlines canceled approximately 300 flights to reinspect its fleet of MD-80 aircraft due to the very same wiring concerns. Delta is reexamining 117 of its MD-88 planes and 16 of its MD-90's.

American said inspections will continue throughout the evening, but the carrier has not yet cancelled any flights for Thursday.

American is rotating its MD-80 aircraft back into service as soon as they are cleared. The airline said Wednesday afternoon that it has so far found 80 airplanes in need of modification.

The need for the unscheduled inspections emerged during a FAA audit of the Fort Worth, Texas-based airline's maintenance records.

A statement this morning from American said that during that audit, a team of American Airlines and FAA inspectors became concerned about the documentation of mandated fixes to "how a certain bundle of wires is secured to the MD-80 aircraft."

"We are reinspecting the MD-80s to make sure the wiring is installed and secured exactly according to the directive," the statement said.

The FAA said today this was not a safety issue and explained that the inspection concerns a wiring bundle in the airplanes' wheel well. The airline is required to secure every one inch, and the aircraft in question may have had the bundles secured every 1 1/4 or 1 1/2 inches.

The FAA is taking extra precautions on the heels of accusations that Southwest Airlines missed, or failed to document, airplane inspections. That prompted the FAA to announce it was proposing a $10.2 million fine against the carrier -- the largest fine ever imposed against a passenger airline.

Last week, the FAA announced a more far-reaching audit to ensure all airlines — more than 100 of them — are complying with maintenance requirements.

FAA inspectors plan to complete their initial review by Friday. It will follow up with a more extensive audit, scheduled for completion in late June.

Preliminary results of the FAA's audit of shows a "very high rate of compliance," according to FAA spokesperson Laura Brown.

American Airlines said "many inspections have already been completed and the aircraft are currently in service," according to its statement.

The company operates 300 MD-80 aircraft, all of which are part of this reinspection.

Congress plans to further examine airline inspection issues next month.

Source: abcnews.com