The FAA is blaming nationwide flight delays and cancellations today on a software configuration glitch within the FAA Telecommunications Infrastructure (FTI) in Salt Lake City.

The problem started at roughly 05:00EST when a router issue disrupted a number of air traffic management services including flight plan processes, an FAA spokeswoman says, making FAA services for traffic flow and flight planning unavailable electronically.

That meant between the time the failure was discovered and when the problem was solved around 09:00EST, carriers had to send flight plans to the FAA via fax or e-mail. The FAA then had to manually input the information into its system.

Though Air Traffic Control (ATC) radar and aircraft communications were not impacted by the glitch, and critical safety systems continued to operate, the spokeswoman says the National Airspace Data Interchange Network (NADIN), which is the computerized system for processing flight plans, was impacted because it relies on FTI services.

Controllers had to revert to managing flight plan data manually during the outage, per agency contingency plans, the FAA spokeswoman explains.

FAA technical and safety exports continue to investigate the outage but there is no indication that the failure was due to a cyber attack.

In addition, Administrator Randy Babbitt is meeting with the Harris Corporation, which manages the FTI contract, to discuss corrective and preventive measures, the spokeswoman adds.

During the roughly four-hour outage, flights were cancelled and delayed across the US.

The National Air Traffic Controllers Association (NATCA) says airport efficiency was cut by at least half during the outage at facilities such as New York JFK, and that controllers were forced to space aircraft operating in New York airspace 20 miles (32.2km) apart.

Spacing has returned to normal and NATCA is not reporting any more problems but it will take the rest of the day to catch up on the flight backlog, a union spokesman says. He adds that he expects operations to return to normal tomorrow.

In the meantime, lingering effects from the outage have resulted in continuing flight delays at locations including Chicago O'Hare and Midway International airports.

"At O'Hare, airlines are reporting 20 minute delays for some flights, with minor cancellations reported," airports operator the Chicago Department of Aviation says in a statement. "At Midway, airlines are reporting delays averaging 30 minutes, with flights to and from the East Coast delayed up to 90 minutes. A few cancellations have been reported at Midway."

AirTran Airways contends that all airlines and airports in the US have been impacted.

The low-cost carrier itself cancelled 42 flights and dozens more had been delayed as of 10:00EST due to flight plan filing issues at the FAA, an AirTran spokesman says.

However, the airline is now "relatively back to normal and should be completely up to speed by day's end" the spokesman says.

Source: Air Transport Intelligence news