DALLAS - Federal regulators are proposing more maintenance-related penalties against American Airlines.

The Federal Aviation Administration said Friday it would fine American $787,500 for three cases of alleged maintenance problems.

In the most serious case, regulators say American operated a plane without replacing a central air data computer on the jet. The McDonnell-Douglas jet has two such computers, which tell pilots the speed and altitude of the plane.

In April 2008, pilots landing in Los Angeles noticed warning indicators going off, and mechanics traced the problem to the computer, according to an FAA document. Instead of fixing the computer as required by federal rules, the mechanics wrote up the incident as a problem with the auto throttle and the plane flew 10 flights with a broken computer, the FAA said.

Another case involves inadequate inspections of rudder components on some Boeing 757 jets. In the third incident, the FAA said mechanics sent a plane back into service before final steps of a thorough maintenance review were checked off as completed.

American has 30 days to respond to the FAA.

Airline spokesman Tim Smith said American was reviewing the FAA charges and will meet with regulators to discuss the proposed penalties.

"American Airlines is very proud of our safety record and our employees' commitment to safety every day," Smith said.

The fine proposed Friday is the latest in a series of penalties American faces for maintenance violations.

According to people familiar with the situation, the FAA is close to proposing a multimillion penalty against American for failing to properly secure wiring in its large fleet of MD-80 series aircraft.

In 2008, the FAA ordered American to pay a $7.1 million fine for a variety of violations, including making 58 flights with two jets that had problems with their autopilot systems. Regulators and airline officials are still discussing that case.

This year, the FAA proposed two separate penalties totaling $5.4 million against American's regional carrier, American Eagle. In one case, regulators said mechanics didn't follow government standards on repairing landing gear doors. In the other, they said Eagle didn't make sure crews had accurate information about baggage loads and a few planes were too heavy for safe takeoff.

American has characterized many of the FAA's charges as paperwork and not related to safety. The airline also claims it is the only U.S. carrier that does all of its own major maintenance work while others have outsourced jobs.