American trying to curb disruptions

American Airlines added five flights today as employees worked to rebuild US schedules and accommodate passengers stranded in yesterday's grounding.

The extra trips, coupled with the scrubbing of about 100 flights as American shuffled flight crews and planes, showed the lingering effects of a computer outage that sidelined the carrier's US fleet.

American parent AMR Corp. didn't say what caused the outages at the third-largest U.S. carrier. The malfunctions began about 10:30 a.m. Dallas time, and systems were restored about 3:30 p.m., said Andrea Huguely, a spokeswoman.

"We do have redundancies in our systems," Chief Executive Officer Tom Horton said in a video posted on the Fort Worth, Texas-based airline's website. "Unfortunately, in this case we had a software issue that impacted both our primary and backup systems."

The carrier is "very sorry" for disrupting passengers' travel plans, Horton said. A combined 978 flights were canceled at American and AMR's American Eagle regional unit.

American, which is preparing to merge with US Airways Group Inc., is allowing passengers with flexible schedules to change reservations at no charge and is providing full refunds to those who can't alter plans.

"This is a technology emergency," Henry Harteveldt, an analyst at Hudson Crossing in San Francisco, said yesterday. "I don't think American has experienced anything like this in a long time, if at all."

United Continental Holdings Inc. in November struggled with its third computer failure of the year when the dispatching system failed, interrupting service for about two hours.

In March of last year, Chicago-based United's website and airport kiosks were disrupted when the company combined reservation systems for United Airlines and Continental Airlines Inc. following their 2010 merger.

In 2008, a failure in US Federal Aviation Administration software that processes flight plans caused hundreds of delays in the eastern half of the U.S., as FAA workers were forced to manually enter data and rely on another processing system in Salt Lake City.