The nation's aging airline fleets, already struggling with high fuel costs and growing passenger demand, delivered another blow to travelers Wednesday as American Airlines and Delta Air Lines canceled hundreds of flights while planes were reinspected for compliance with federal maintenance rules. More disruptions are expected today.
Experts said the airlines' decision to voluntarily ground the planes didn't signal that they were unsafe. But the episode is the latest indication that a combination of aging aircraft and schedule reductions are leaving the industry with fewer options.
U.S. airlines, beset by financial woes that have forced them to postpone capital investments, operate some of the oldest fleets in the world, noted Richard Aboulafia, an analyst with the Teal Group.
Older aircraft need more upkeep, which can result in more down time.
"This isn't a safety issue," he said. "But reliability is becoming a concern due to the age of the fleet." And with fewer planes, the carriers also are hard-pressed to re-book passengers onto other flights when there are cancellations for inspections or other reasons.
American, which was forced to cancel more than 320 flights Wednesday as it performed maintenance checks on its MD-80 jetliners, said it may have to cancel more flights today as it completes wiring inspections and repairs.
Maintenance issues have been high profile at America's airports for weeks as carriers scramble to bring maintenance inspections up to date after a recent Federal Aviation Administration crackdown. On March 6, the FAA assessed a $10.2-million fine against Southwest Airlines.
Since then United Airlines, American Eagle, American and Delta have conducted voluntary inspections, and more may be ahead.
At Los Angeles International Airport on Wednesday, American canceled 10 of 92 domestic flights, affecting about 1,000 passengers.
"It's good to know that they're taking precautions, but I'm still nervous that there are problems in the first place," said Amy Isenberg of Los Angeles, who was waiting for an American flight to Nashville. American has more flights into and out of LAX than any other carrier.
American said it also canceled a flight at Ontario International Airport and four flights at San Diego International Airport.
American had inspected about 200 planes by Wednesday afternoon and found that 80 required being taken out of service while modifications were being made to wiring bundles near the landing gear, spokesman Tim Wagner said.
The cancellations represented about 13% of the day's schedule for the nation's largest carrier and between 25,000 and 30,000 passengers were affected as flight schedules were disrupted across American's domestic route system.
"This was not related to an incident or issue that would have endangered passengers," Wagner said, adding that the inspections were carried out in cooperation with the FAA.
American said 95 MD-80s that flew normal schedules Wednesday still needed to be inspected Wednesday night and today. Those checks probably would require an unspecified number of flight cancellations today, the airline said.
Delta added to travelers' woes when it said it would have to cancel some flights today while it inspects the wiring bundles on its fleet of 133 MD-80 and MD-90s. Delta said it hoped to re-book passengers when necessary. The inspections are expected to be completed by Saturday.
Among big U.S. carriers, American operates the second-oldest fleet, with an average age of 14 years, according to a new study by AirlineForecasts, a Washington-based consulting firm. Many of American's 300 MD-80s were built in the late 1980s, according to the study.
Northwest Airlines has the nation's oldest fleet of planes, with an average age of about 20 years, the study found.
Flying older planes puts U.S. carriers at a disadvantage when competing with foreign carriers such as Singapore Airlines and Lufthansa that are adding new planes at a faster pace, said Vaughn Cordle, chief analyst at AirlineForecasts.
Aging planes burn more fuel -- an important consideration as oil prices hover near record highs -- and lack many of the amenities passengers demand, such as state-of-the-art entertainment systems.
American carriers "can't compete on the global playing field given the kind of low-cost competition coming to our shores with newer fleets," Cordle said.
The U.S. has recently entered into so-called open skies agreements with the European Union, Australia and other nations.
The pacts, which open the world's major airports to more competition, will make it easier for U.S. carriers to enter foreign markets and clear the way for more foreign airlines to offer service to more destinations in the United States.
The effect of pulling airplanes out of service for unscheduled maintenance inspections was demonstrated two weeks ago when Southwest had to ground dozens of planes while they were inspected for fuselage cracks.
The inspections forced the carrier to cancel 126 flights.
American Eagle, a corporate sister of American Airlines, later grounded 25 planes and canceled a handful of flights while inspection paperwork was updated.
And United Airlines reinspected instruments on seven of its 747 jumbo jets, although no flights were canceled.
The flurry of maintenance issues also has focused attention on the out-sourcing of aircraft maintenance.
Southwest dropped plans to move some of its aircraft maintenance from the U.S. to El Salvador after the FAA fine was announced.
In the case of the United 747s, FAA inspectors discovered that Korean Airlines, which contracts with United to perform maintenance, had failed to calibrate an instrument used to check the jetliners' altimeters.
Whatever the competitive landscape, travelers at LAX on Wednesday made it clear that they didn't want airlines to cut corners on maintenance, even if it resulted in delays.
As a frequent business traveler, Boston-based insurance executive Linda Wentworth, 44, said she was used to flight delays, like the one that pushed her flight to Massachusetts back more than an hour.
"I wish the maintenance could be done on a pro-active basis, and it's always frustrating to wait when you're trying to get home," she said. "But safety is key."
Times staff writer Molly Hennessy-Fiske contributed to this report.