![This March 12, 2013, file photo shows the air traffic control tower at Chicago's Midway International Airport.](https://img.huffingtonpost.com/asset/63bea3c52100006800dce363.jpeg?cache=7v8Wci9oNb&ops=scalefit_720_noupscale)
Air traffic across the U.S. slowly resumed Wednesday after domestic flights were temporarily grounded due to an outage of a system the Federal Aviation Administration uses to notify pilots of important information.
The FAA said in an advisory that its Notice to Air Missions system had “failed” and initially gave no estimate for restoration of the service. The system provides urgent advisory information to flight personnel about things like airport conditions, runway closures and obstacles.
Shortly after 7 a.m. Eastern, the FAA ordered airlines to halt all domestic departures until 9 a.m. to “allow the agency to validate the integrity of flight and safety information.”
Just before 9 a.m., the FAA announced that normal operations “are resuming gradually across the U.S.” and that the ground stop had been lifted. The agency said it was still investigating the cause of the system failure.
Rep. Rick Larsen (Wash.), the top Democrat on the House Transportation and Infrastructure Committee, told CNN that he and many of his colleagues will have questions about what caused the mess.
“We don’t know if this was just a technology issue or if it was something deeper,” Larsen said. It “begs the question about the current state of the technology infrastructure at the FAA.”
The disruption comes not long after winter storms caused travel chaos over the busy holiday season. There were nearly 6,000 canceled flights and 12,000 delays in the U.S. on Dec. 23, 2022, CNN reported. The disruption extended to deliveries, trains and bus travel, and Buffalo’s Niagara International airport was closed for days.
Although Wednesday’s ground stop has been lifted, the knock-on effects of the outage continue. As of 10 a.m., nearly 5,000 flights within, into or out of the U.S. had been delayed, and nearly 900 canceled, according to the FlightAware tracker.
During the outage, United Airlines temporarily grounded all U.S. flights, the airline tweeted. Southwest Airlines — still in reputation recovery mode after a chaotic holiday season full of cancellations — said it was “closely monitoring a data issue with the FAA.”
Delta Air Lines is “safely focused on managing our operation during this morning’s FAA ground stop for all carriers,” the company told HuffPost in a statement. “We will provide more updates about our operation today as soon as we can.”
Transportation Secretary Pete Buttigieg briefed President Joe Biden on the situation in the morning, White House press secretary Karine Jean-Pierre said.
“There is no evidence of a cyberattack at this point,” Jean-Pierre wrote in a tweet. She added that the president has directed “a full investigation into the causes.”
Biden told reporters at the White House: “Aircraft can still land safely, just not take off right now. They don’t know what the cause of it is, they expect in a couple of hours they’ll have a good sense of what caused it and will respond at that time,” according to the pool report.
Airports and airlines urged passengers Wednesday to check the status of their flights before heading to the airport.
Aviation analysts interviewed by MSNBC said that it was highly unusual for the NOTAMS system to crash.
“For this NOTAMS system to be out, which I don’t ever remember it failing before, and I’ve been flying 53 years ... I think the FAA is doing all that they can,” said pilot John Cox.