ATLANTA -- Air travelers nationwide scrambled to revise their plans Thursday after an FAA computer glitch caused widespread cancellations and delays for the second time in 15 months.
The Federal Aviation Administration said the problem, which lasted about four hours, was fixed about 9 a.m., but it was unclear how long flights would be affected.
It started when a single circuit board in a piece of networking equipment at a computer center in Salt Lake City failed about 5 a.m., the FAA said in a statement.
That failure prevented air traffic control computers in different parts of the country from talking to each other. Air traffic controllers were forced to type in complicated flight plans themselves because they could not be transferred automatically from computers in one region of the country to computers in another, slowing down the whole system.
Two large computer centers in Salt Lake City and near Atlanta were affected, as well as 21 regional radar centers around the country.
Delays were particularly bad at Hartsfield-Jackson Atlanta International Airport, the world's busiest. The glitch also exacerbated delays caused by bad weather in the Northeast, with airports in the Chicago, Washington, D.C., and New York metro areas reporting problems.
Some flights were more than two hours behind schedule. Airports around the South also reported delays and cancellations.
U.S. Sen. Charles Schumer, D-New York, said the country's aviation system is ''in shambles'' and the FAA needs more resources to prevent such problems from continuing.
''If we don't deliver the resources, manpower, and technology the FAA it needs to upgrade the system, these technical glitches that cause cascading delays and chaos across the country are going to become a very regular occurrence,'' he said in a statement.
Despite the problems, the public areas of Atlanta's airport seemed no busier than usual. Travelers ate breakfast and lounged in the atrium, where sisters Sharon Walker and Sheila James waited to take their elderly mother, Rosa Washington, to see their other sister in St. Louis. The trio's 9:30 a.m. flight was delayed until 4 p.m. because of the glitch.
''We were going to be there for a four-day weekend, but now it's getting cut short,'' James said. ''It's just not a good day.''
In the public areas of Newark International Airport, where delays are routine, Thursday seemed like a normal day, though several people paced around the terminal trying to rearrange their plans. Passenger Chris Cozzi said he was moved from one Delta flight to another but was still unsure if it would arrive on time in Atlanta, where he would have just an hour to catch a flight to Europe.
''You have to wonder what's the glitch? Glitch is kind of a general term, it could encompass many, many things,'' he said. ''So it is a concern, but I tend to be an optimist.''