United Airlines faced a systemwide computer system outage Tuesday afternoon, which was expected to have a significant impact on passengers this evening.
The passenger service system, used for reservations, ticketing and check-ins went down shortly after 2 p.m. and caused delays and cancellations, according to a statement released by the airline.
The network outage also affected the company's website Tuesday afternoon, but the site was back up and running as of 5 p.m.
According to flightaware.com United's systemwide outage ended about 4:20 p.m., but there will likely be delays throughout the night.
The system which went down, called SHARES, is from Continental Airlines and was taken up by United on March 3, according to flightware.com.
At 5:30 p.m., United tweeted, "We're in the process of resuming operations and rebooking customers," and added the airline issued a waiver policy that will allow affected customers to cancel or rebook without penalty.
United acknowledged at least 200 delayed flights and passengers in several United hubs reported very long lines at ticket counters. During the outage, the airline stopped sending planes to Newark, N.J., and San Francisco.
Passengers in several United hubs reported very long lines at ticket counters.
Alex Belo was waiting at Newark to get on a flight to Mexico City. He considered himself lucky to be behind only 100 or so people waiting to check a bag -- because there were another 300 to 400 behind him.
"The line is not moving, or very slowly moving. And they're giving priority only to first class," he said.
United said it will not charge the usual change fees for passengers on affected flights who want to cancel or rebook their tickets.
Simon Duvall spent two hours sitting on his flight waiting for the computer problems to be resolved. People were calm but not happy, he said.
"We're on a plane, on the tarmac in Las Vegas in the middle of August. It's warm. It's uncomfortable. It's cramped," he said.
United Continental Holdings Inc. has been struggling with computer issues off and on since March, when it switched to using Continental's system for tracking passenger information. The two airlines merged in 2010.
Airlines rely on software to know who is filling the seats on its planes, and how many seats are available. Those computer systems make it possible to print boarding passes, too.
Rich Pearson, head of marketing at professional freelance site Elance, was stuck in Houston on his way to present at a jobs seminar at the Republican convention in Tampa.
Planes were lined up on the tarmac. "It's almost like horseback riding when they are all nose-to-butt," he said. "It's like we've gone back 50 years."
"People are relatively calm," he added. "The customer service area was initially flooded. But they can't really do anything."
• Daily Herald wire reports contributed to this account.