WASHINGTON (AP) — Trump administration officials said Friday that new technology being added to the nation’s air traffic control system overloaded antiquated parts of it and caused “intermittent” communications and radar gaps, leading to the longest nationwide ground stop in 25 years.
It was lifted in the evening after a five-hour stretch when most flights were not allowed to take off from airports in the U.S.
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Thousands of flights and potentially over a million travelers were affected. Secretary of Homeland Security Markwayne Mullin told reporters at the White House that no one was in any danger as more than 3,000 flights were safely landed. But Secretary of Transportation Sean Duffy said he could not guarantee it wouldn’t happen again.
Mullin said the FAA was installing “new equipment, new technology” and “it was overwhelming the older system.” There appeared to be no indication of a cyberattack, he said.
A limited number of domestic flights began departing late Friday after the ground stop was lifted, but it will likely take days for airlines to fully recover because so many planes and crews were out of position. Officials said they think the system will be back to normal in time to handle the Thanksgiving travel rush.
The nationwide ground stop was the first since January 2023, when another key FAA computer system that sends notices to pilots malfunctioned, and the second since the aftermath of the Sept. 11, 2001, attacks.
Asked whether he could rule out a cyberattack or rogue artificial intelligence incident, Mullin said there are no “footprints” showing an attack and that the problem appears to be “mechanically driven.” He said officials were still looking for the cause.
At least 827 flights had been diverted. By 7:05 p.m. EST, 670 flights were sent back to the airport from where they originally took off, while 157 were redirected to a different airport, according to Cirium, an aviation analytics company.
Duffy was defensive, blaming Congress for failing to approve more funding for new technology, while downplaying the fact that trying to implement new fixes overtaxed the system. He implored lawmakers to act.
“By doing nothing, you inject way more risk into the system,” he said.
Duffy said he expected flights around the country to be “back up and operational as we come into the heat of travel” next weekend ahead of Thanksgiving, but he also suggested more disruptions might occur.
“We didn’t think we would have this kind of outage. We did,” he said, while also noting, “We were able to review what went wrong, and then reboot the system and go. But, you will have more of these.”
Duffy said the problems were not linked to the FAA’s new AI-powered system the agency is rolling out to help predict problems in the sky because that isn’t connected to what failed on Friday.
“This is all the old legacy equipment. All of the new equipment that’s been deployed did not go down,” Duffy said.
The FAA has already replaced thousands of old copper wires with fiber optic lines and upgraded hundreds of radio systems as part of the overhaul that began last year after Congress approved $12.5 billion of funding. Duffy and the White House are pushing for $30 billion more to complete the work.
Many flights ended up being diverted to places including Washington Dulles International Airport, Los Angeles International Airport and Nashville International Airport.
Some 11,000 flights carrying more than 1.5 million passengers had been scheduled to take off from airports in the U.S. after 4 p.m. EST.
At the time of the ground stoppage, more than 3,500 airplanes were in the sky, Duffy said.
At Chicago O’Hare Airport on Friday, travelers passing through security learned about the ground stop when they looked up at screens that showed flight delays across the board. Some called friends or family members, debating whether to stay the night in Chicago or find another way to their destinations.
Amber McQuilkin, 27, sat on a bench, disappointed that she might miss a trip with friends to New York for the League of Legends world finals.
“There’s not really any information being passed to me,” said the Seattle software engineer. “I contemplated just abandoning the flight and driving, but then the more I thought about it, the more I’m like, that would be miserable.”
Ruth Coles was still stuck on her plane five hours after it landed at the Los Angeles International Airport from Newark even after the ground stop was lifted. She said they were told they were waiting for a gate to open up.
“The pilot keeps saying they are telling him we are next in line,” Coles said, but that was several hours ago.
NBA, NHL and college teams were left stranded as they tried to reach their destinations. Meanwhile, NFL teams were left to wonder whether the issue would be resolved in time to travel to their games this weekend.
Duffy said NCAA teams will be prioritized ahead of football games on Saturday.
“I would encourage those football teams to reach out to the FAA, to schedule their flight times and make sure they can move” to make their kickoff, he said.
Cargo flights were also delayed by the ground stop.
FedEx, the world’s largest cargo airline, said it was prepared to activate contingency plans to keep any possible disruptions at a minimum.
U.S. airlines move about 61,000 tons (55,340 metric tonnes) of goods — from letters to packages — to and from more than 220 countries daily, according to the industry trade group Airlines for America.
The problem appeared similar to a regional air traffic control communication outage in September that snarled hundreds of flights across the Northeast, although that disruption was linked to a construction crew cutting a fiber optic line. Aging equipment was also blamed for the brief radar outages last year that disrupted Newark airport.
Aviation safety expert Steve Arroyo said the difference this time is that it happened on a nationwide scale that left controllers unable to reliably talk to pilots.
“If you don’t have that ability, whether it’s because the old wires that they have are just run down or for whatever reason, you’ve got to stop airplanes on the ground and not put them in the air, where you’re going to risk not being able to communicate with them,” said Arroyo, a former United Airlines pilot.
Friday’s ground stop was also different than the one after 9/11 because planes were not being told to land immediately and pilots likely were able to communicate with ground controllers at airports, Arroyo said.
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Funk reported from Omaha, Nebraska. AP writers Mead Gruver in Fort Collins, Colorado; Ali Swenson in Chicago; Alex Veiga and Jaimie Ding in Los Angeles; Seung Min Kim and Aamer Madhani in Washington; Hannah Schoenbaum in Salt Lake City; and Hallie Golden in Seattle contributed to this report.
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This story has been corrected to show the Sept. 11 attacks were in 2001.
