FAA outage: Officials say corrupt file caused grounding of flights

Over 500 US flights have been delayed and 76 cancelled as of early Thursday, after a technical glitch the day before grounded flights nationwide.

The exact cause remains unknown but early investigations by the Federal Aviation Administration (FAA) said it was due to a "damaged database file".

Flights began to resume on Wednesday morning, though airlines warn delays could continue into Friday.

Airports nationwide were affected, from Denver to Atlanta to New York City.

Major airlines including Delta Airlines, United Airlines, American Airlines Group Inc and Southwest Airlines announced they expect normal operations on Thursday.

"At this time, there is no evidence of a cyber attack", the FAA said.

A senior government official said a corrupted file caused the issue, affecting both the primary and backup systems of the FAA's Notice to Air Mission system, or NOTAM, NBC News reported. Officials continue to investigate the issue, they said.

By Wednesday night east coast time, over 11,000 flights in and out of the US had been delayed and more than 1,300 were cancelled.

The technical issues marked the first time in nearly two decades that flights across the US were grounded.

Since operations have resumed, delays are expected to continue as airlines try to get planes in and out of crowded gates. Limits on how long staff can work may also have an impact.

Captain Chris Torres, vice-president of the Allied Pilots Association, warned that Wednesday's airline drama was not going to immediately disappear. "This is going to cause ripple effects," he told Reuters.

President Joe Biden called for a "full investigation", the White House press secretary said on Wednesday.

US Department of Transportation Secretary Pete Buttigieg told CNN that the FAA had grounded flights out of "an abundance of caution" after it noticed irregularities with its Notice to Air Missions System.

Mr Buttigieg said his "primary interest" moving forward "is understanding exactly how this was possible and what steps are needed to make sure it doesn't happen again".

The Notice to Air Missions System provides real-time safety information to pilots "about closed runways, equipment outages, and other potential hazards along a flight route or at a location that could affect the flight", according to the FAA.

Officials said they are still working to determine the root cause of the issue.

Still recovering from a series of recent wide scale flight disruptions over the holidays, major US airlines moved to assist weary travellers.

United Airlines said it would waive change fees and any difference in fare for customers rescheduling flights departing on or before 16 January 2023.

Delta airlines extended a fair difference waiver to passengers "even if their flight isn't delayed or cancelled", looking to offer "additional flexibility".

For international passengers, Air Canada - the foreign carrier with the most flights into the US - said it would put in place a "goodwill policy" so affected passengers can change their travel plans.