American Airlines canceled 325 flights on Wednesday to conduct maintenance inspections on its MD-80 aircraft.

American Airlines MD-80s at Chicago O’Hare Airport

The Kansas City Star reported that “The grounding of the planes occurred following a joint audit conducted by American and Federal Aviation Administration officials, according to the airline.”

Maintenance teams examined the aircraft at the gates to check the distance between two insulated wire bundles. Fortunately, it was not necessary for the aircraft to go to American’s maintenance facility for the inspection. Virtually all of the 298 aircraft are expected to be back in service today.

American has an outstanding safety record on the MD-80, an aircraft that entered service in 1980. Every four years, each MD-80 goes to American’s maintenance facility in Tulsa, Oklahoma where it is torn apart and rebuilt with the latest equipment. (See the CNBC video below to watch them tear apart an aircraft.)

The MD-80 has been the workhorse of the American fleet. My home airport is Austin, Texas, and the MD-80 is American’s most widely used aircraft at this location, offering non-stop service to cities as distant as Chicago, Los Angeles, San Jose, and Seattle. However, it is also one of the least fuel efficient aircraft in the fleet, a definite liability in this time of surging fuel costs. American will eventually replace its 298 MD-80s with more fuel efficient aircraft, but until then, they will continue to be the most widely used aircraft in its fleet.