The federal government wants to fine American Airlines a record $24.2 million for failing to adequately address a problem with wheel-well wiring that could cause fires in its fleet of 245 McDonnell Douglas MD-80 airplanes.

The Federal Aviation Administration proposed the fine Thursday, alleging that American failed to follow a 2006 directive to inspect the wiring to auxiliary hydraulic pumps for signs of wear that could send sparks flying next to fuel tanks in the wings.

The FAA inspected several American Airlines planes two years later and determined that the directive had not been obeyed.

The airline said it would fight the fine.

"These events happened more than two years ago, and we believe this action is unwarranted," American said in a statement. "American Airlines has always maintained its aircraft to the highest standards, and we continue to do so. We assure our customers there was never a safety of flight issue surrounding these circumstances."

The FAA detailed the problems its inspectors found in a 58-page letter Thursday addressed to American President Thomas W. Horton. It lists screws, clamps, washers, grommets, locknuts and "nutclips" that should have been installed under the 2006 directive.

American has more than 900 aircraft in its fleet. It has begun phasing out the fuel-thirsty MD-80, which debuted in the 1960s as the DC-9 before evolving into the current model in the 1970s. American has retired 55 of the planes, which carry up to 170 passengers on short and middle-distance flights.

To date, the largest fine proposed by the FAA was $10.2 million against Southwest Airlines in 2008 for failing to inspect older planes for cracks. Southwest fought the fine but settled the matter by paying $7.5 million.

The decision to hit American with a proposed fine more than double that faced by Southwest was endorsed by U.S. Transportation Secretary Ray LaHood.

"We put rules and regulations in place to keep the flying public safe," LaHood said. "We expect operators to perform inspections and conduct regular and required maintenance in order to prevent safety issues."