The incident, which began overnight from Tuesday to Wednesday, affected a crucial information system for pilots and crews.

To ensure the safety of air traffic, the FAA decided to prevent all takeoffs of domestic flights until 09:00 on the east coast of the country (1400 GMT), with a few exceptions, the time to resolve the problem.

More than 1,100 flights were canceled and more than 7,300 were delayed, according to a count from the specialized site Flight Aware around 5:30 p.m. GMT.

Cause unknown

At Ronald Reagan airport, located near Washington, the departure boards were riddled with red flags indicating delays.

"We're going to miss our connection," said Lisa Nho, who was waiting with her almost two-year-old daughter for a flight to Texas, to be followed by another flight to Cabo, Mexico.

"We were leaving when we received a text saying that the flight would be delayed," she explained.

Vince Hamilton's flight to Chicago had already been delayed twice.

If he misses his connection in St. Louis, where he's supposed to catch a bus, he plans to rent a car.

At Mexico City airport, several flights to the United States were also delayed, noted an AFP journalist.

An employee at Los Angeles International Airport walks past a plane docked at a gate on January 11, 2023 © Stefani Reynolds / AFP

Attention is now focused on the cause of the failure, which has not yet been identified by the FAA.

Asked about the subject before the take-off ban was lifted, US President Joe Biden said he spoke with his Minister of Transport, Pete Buttigieg, but did not know the origin of the breakdown at the time.

Regulators "expect to have a better idea in a few hours and will react at that time," he said.

White House spokeswoman Karine Jean-Pierre said on Twitter that there was at this stage "no sign that this was a cyberattack".

Pete Buttigieg called for an investigation "to determine the causes (of the outage) and recommend next steps."

"Unacceptable"

The chair of the US Senate Committee on Transportation, Maria Cantwell, also warned that a committee would examine the causes of the disruptions.

“The public needs a resilient air transport system,” said the elected Democrat in a press release.

Air traffic in the United States had already been badly shaken at Christmas time by an extreme cold spell accompanied by snowfall, which had caused cascading cancellations for several days within the Southwest company.

"Today's catastrophic failure of the FAA system is a clear signal that America's transportation system is in desperate need of a major upgrade," the Tourism Association of America said.

Several Republicans have also strongly criticized the FAA, like Senator Ted Cruz who, in a press release, considered "unacceptable" the inability of the agency to operate a system important to safety.

Passengers wait near their gate at Los Angeles International Airport on January 11, 2023 © Stefani Reynolds / AFP

The FAA has been without a named chief since the resignation of Steve Dickson at the end of March 2021. The White House proposed in July to replace him with Phillip Washington, but Congress has still not heard him, thus preventing his taking office.

The Notice To Air Missions (NOTAM) system, affected by Wednesday's outage, makes it possible to transmit information to flight crews concerning risks in airports, such as work on a landing strip, for example.

This system is "essential in the information required for the conduct of ground / air operations", explained to AFP Michel Merluzeau, analyst for the AIR cabinet.

A total of 21,464 flights are expected to take off from the United States on Wednesday, the vast majority being domestic routes, according to figures from specialist firm Juliett Alpha.

Around 2 million passengers could potentially be affected by the incident.

© 2023 AFP