It didn't address another potential problem the inspector general raised. Scovel told Congress that 44 percent of FAA inspectors are eligible to retire by 2010, and questioned whether the agency's request for funds to hire 203 safety inspectors in fiscal 2008 is sufficient to offset retiring staffers.
Aircraft maintenance is fast becoming an issue on Capitol Hill, where Congress will be asked this year to reauthorize the FAA's existence for four years. The agency's authorization expires Sept. 30.
"We're going to make sure that more money is appropriated to hire inspectors,'' said Rep. James Oberstar, D-Minn., who chairs the House aviation subcommittee. "We have to make sure that this maintenance and repair work is being done right.''
Foreign repair stations have also attracted congressional attention. Last week, several members of the House introduced HR1981, which would direct the FAA and Transportation Security Administration to impose tightened security rules and audits on foreign repair stations.
But the Air Transport Association, and airlines themselves, say the maintenance picture is both more reassuring and more complex than critics would have it.
For example, United Airlines, the world's No. 2 carrier by passenger traffic, does much of its maintenance in-house, outsources some work and takes in some work.
United operates its largest maintenance base near San Francisco International Airport. It employs 3,000 workers and specializes in overhauling jet engines and working on landing gears, said United media relations manager Megan McCarthy. In addition to working on its own planes, United repairs and maintains aircraft for Air China and Korean Airlines at the SFO plant, McCarthy said.
According to McCarthy, the airline outsources work to bases in the United States and in foreign countries. Boeing 777s are sent to China for service. Boeing 747s go to Pusan, South Korea, where they are maintained by Korean Airlines, which United also counts as a customer in San Francisco.
Local 9 of the Aircraft Mechanics Fraternal Association, which represents United mechanics, recently cited an independent audit showing that the carrier outsources 30 percent of its maintenance -- above the 20 percent cap agreed to in union contracts. But United, using other formulas, said the figure is an allowable 16 percent.
An unspecified amount of United's maintenance is done outside the United States. United has full confidence in the work, McCarthy said. "Safety is our No. 1 priority.''
By contrast, American Airlines, the world's largest airline, has kept nearly all of its maintenance -- including all of its heavy maintenance -- in the United States. Additionally, the carrier has retooled its primary maintenance facility in Tulsa to work on planes for clients such as Allegiant Airlines and North American Airlines, as well as its own planes. 'Going for $90 million'
American's maintenance division, once a cost drain, now makes money, says Carmine Romano, American's vice president for base management at the Tulsa base. American employs 7,000 workers there, which it says is the world's largest aircraft repair station.
"Last year, Tulsa brought in $35 (million) to $40 million in revenue,'' Romano said. "For 2007, we're going for $90 million.''
American has said it plans to invest up to $100 million in its maintenance operations, a move made possible because it has returned to profit. Parent company AMR Corp. earned $81 million in the first quarter of this year, its fourth consecutive profitable quarter, following layoffs in 2003 and $8 billion in losses from 2000 to early 2006.
U.S. airlines are sensitive to charges that they risk cutting corners on safety when they expand outsourcing. But the carriers say the work can be, and is, done well by trained contractors at high-tech overseas hubs such as Germany and Singapore.
"Commercial airlines have utilized contract maintenance for decades,'' said Basil Barimo, vice president of operations and safety at the Air Transport Association, last month. ''Critics of contract maintenance argue that if airlines don't perform all of the maintenance themselves, then they can't be safe. Independent data from the National Transportation Safety Board proves them wrong.''
Last week, several House members introduced a bill to direct the FAA and Transportation Security Administration to impose tightened security rules and audits on foreign repair stations.
The American aviation system is the safest in the world, in part because of the quality of the repair and maintenance systems that help keep those jumbo jets aloft.
Almost half the 5,000-employee Atlanta shop's engine overhauls --- which can take two months and cost $1.5 million --- are for outside customers.
The FAA's voluntary process for airlines to report their top 10 "critical maintenance" providers has produced reports from only seven of nine carriers.