The US aviation regulator ordered airlines to pause all domestic departures until later on Wednesday morning after a computer system outage prompted widespread cancellation of flights and delays.
The Federal Aviation Administration said it was working to restore its Notice to Air Missions System (Notam), which alerts pilots and crew to important information related to flight operations, following an outage.
The agency said in a tweet after 7am eastern time that it has had ordered airlines to pause all domestic departures until 9 a.m. Eastern Time to allow the agency to validate the integrity of flight and safety information.
More than 1,200 flights were delayed within, into, or out of the US by 7.15am ET, according to FlightAware, a flight tracking service.
The FAA said that access to its National Airspace System remained “limited” as it worked to restore the Notam.
“While some functions are beginning to come back on line, National Airspace System operations remain limited,” the FAA wrote.
At 6.27am Eastern time, United Airlines announced a “ground stop” for all flights until 10am Eastern time.
United wrote on Twitter that it had “temporarily” delayed all domestic flights and would issue an update when it heard more from the FAA.
Another large airline, Southwest Airlines, said it was “closely monitoring” the situation and asked passengers to check their flight status.
Update 3: The FAA is still working to fully restore the Notice to Air Missions system following an outage.⁰⁰The FAA has ordered airlines to pause all domestic departures until 9 a.m. Eastern Time to allow the agency to validate the integrity of flight and safety information.
— The FAA ✈️ (@FAANews) January 11, 2023
Departure boards showed that just three of the 20 flights scheduled to leave New York City’s JFK airport between 05.40 and 6.10am managed to take off.
— United Airlines (@united) January 11, 2023
Overall, nearly 21,500 flights were due to depart US airports on Wednesday, according to aviation data company Cirium.
The problems come less than a month after bad weather triggered mass disruption and thousands of flight cancellations.