DALLAS — The Federal Aviation Administration, under fire for its handling of missed safety inspections at Southwest Airlines Co., said Tuesday it is ordering a check of maintenance records at all U.S. airlines.

The FAA's action applies to records on all planes. FAA inspectors will check to make sure the airlines have complied with orders to perform the type of structural inspections that Southwest missed on some older Boeing 737s.

The FAA hit Southwest this month with a $10.2 million civil penalty for missing the inspections and then continuing to fly the planes with passengers on board even after realizing the mistake. Dallas-based Southwest plans to appeal.

Acting FAA Administrator Robert Sturgell said Tuesday the failure of Southwest to check the fuselages of its planes for cracks prompted him to ensure that other carriers were meeting the same requirement.

"While the data tell us flying is safer than ever, prudence dictates we take this additional precaution and conduct a special emphasis review," Sturgell said.

Sturgell said the first check of the airlines' maintenance records will be done by March 28 and a full audit finished by June 30.

The FAA said it would check compliance with at least 10 safety orders, called airworthiness directives, at every airline by March 28. The agency said a full audit covering at least 10 percent of all safety directives will be finished by June 30.

FAA spokeswoman Laura Brown said the review will involve both examining paperwork and checking airplanes at 118 operators, some of which are very small.

David Castelveter, a spokesman for the airlines' trade group, the Air Transport Association, said the FAA audit would "help create the redundancies that make our aviation system the safest in the world."

A leading FAA critic, Rep. James Oberstar, D-Minn., chairman of the House Transportation and Infrastructure Committee, called the FAA move "a positive step." He has accused the agency of being too cozy with airlines.

In a letter to airline officials, FAA associate administrator for safety Nicholas Sabatini defended the agency's recent strategy of relying more heavily on information from the airlines themselves. FAA and airline officials argue that the system correctly focuses on improving safety instead of finding blame.

Southwest turned itself in to the FAA last March after discovering it had missed structural safety inspections on 46 planes. The company is conducting an internal review, and the FAA is also investigating how the lapses occurred.

After a drumbeat of bad publicity lasting more than a week, Southwest confirmed Monday that it was suspending plans to outsource some of its maintenance work to a contractor in El Salvador.

The Business Travel Coalition, a group representing corporate travel customers, said U.S. airlines outsourcing of maintenance costs rose from 26 percent in 1997 to 64 percent in 2006. The group called for more FAA oversight of repair facilities both in the United States and in foreign countries, with the cost of inspections borne by airlines that outsource maintenance work.

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AP Business Writer Dan Caterinicchia in Washington contributed to this report.