Flight Delays, Cancellations Pile Up After FAA System Outage Grounded US Planes

Thousands of flights across the United States were brought to a standstill Wednesday morning after a computer outage at the Federal Aviation Administration.

The outage of the FAA's Notice to Air Missions System grounded departures around the country, delaying hundreds of flights, with scores more expected to be impacted throughout the day.

Air traffic operations gradually resumed after 9.am. ET when an FAA ground stop ordering a pause on domestic departures had been lifted for all airlines. Late Wednesday, the FAA released a statement saying "preliminary work has traced the outage to a damaged database file."

"At this time," the statement continued, " there is no evidence of a cyber attack."

The pause caused widespread disruptions as all aircrafts are required to route through the system, including commercial and military flights. Flight delays quickly cascaded, with more than 9,000 flights within, into or out of the United States delayed as of Wednesday evening, according to the flight tracking website FlightAware. Over 1,300 flights were also cancelled.

“We are going to see the ripple effects from that, this morning’s delays through the system during the day,” said Transportation Secretary Pete Buttigieg in an interview on CNN. “Now we have to understand how this could have happened in the first place. Why the usual redundancies that would stop it from being that disruptive did not stop it from being disruptive this time.”

The Associated Press reported that more than 21,000 flights were scheduled to take off in the U.S. on Wednesday, and 1,840 international flights were expected to fly into the U.S.

Airports in Chicago, Los Angeles, New York and Atlanta were seeing between 30% and 40% of flights delayed.

The Notice to Air Missions System, also known as NOTAMs, used to be available through a hotline but that was phased out with the internet. The alerts span from mundane information about construction at airports to urgent flight restrictions or broken equipment.

When NOTAM's system initially failed on Tuesday evening at around 8:28 p.m., the FAA resorted back to the telephone hotlines to keep departures overnight flying. However, as daytime traffic picked up Wednesday morning, it overwhelmed the backup system and forced the grounding of flights.

Domestic Flights Temporarily Grounded by Computer Outage: Photos

A spokesman for the U.S. military’s Air Mobility Command said they had not been impacted by the outage. Air Mobility Command is responsible for all the troop movement and supply flights, such as the C-17s that carry the president’s motorcade vehicles when he travels, but also all the flights that transport troops from one base to another.

President Joe Biden addressed the FAA issue Wednesday before leaving the White House to accompany his wife to a medical procedure at Walter Reed National Military Medical Center outside of Washington. He said he was briefed by Buttigieg, who told him they still had not identified what went wrong. Asked by reporters if he thought it was a cyberattack, Biden said "we don't know," but that he had ordered the Department of Transportation to investigate.

Buttigieg told MSNBC's "Andrea Mitchell Reports" that while there doesn't seem to be any indication of "nefarious" activity from domestic or foreign actors, the agency isn't "ruling it out."

"The FBI has spoken to that and the FAA is looking closely at that as well, as they work to see exactly what was going on inside the files that were in this system leading to this irregularity," Buttigieg said. "There is no direct indication of any external or nefarious activity, but we are not yet prepared to rule that out."

European flights into the U.S. appeared to be largely unaffected.

The Paris airports' press office confirmed to NBC News early Wednesday that all American Airlines flights bound for the U.S. had been delayed. However, Air France said their U.S.-bound flights were not impacted by the outage and departed as planned.

Irish carrier Aer Lingus said services to the U.S. continue, and Dublin Airport’s website showed that its flights to Newark, Boston, Chicago and Los Angeles were running on schedule.