FAA Says Contractor Error During Telecom Upgrade Caused Friday's Nationwide Ground Stop

A nationwide ground stop that halted thousands of flights on Friday was declared after an error occurred while a contractor was updating an old Federal Aviation Administration telecommunication line, Transportation Secretary Sean Duffy said Saturday.

Duffy said L3Harris, a longtime FAA contractor, was performing routine maintenance at at least one of the agency's remote locations, converting copper wire to fiber. The routers in those facilities were manufactured in 2001, he said, and such upgrades have been taking place at American institutions for decades. "Virtually every single institution in America has gone from copper to fiber, from analog to digital," Duffy said. "Just maybe the FAA is the last one to be doing this work because the investments haven't been made, but this is not complicated."

The FAA is still investigating the precise error that began flooding other routers in the air traffic control system. Duffy said the work at the remote location was straightforward, and investigators are trying to determine whether there was incompetence, meaning user or installer error by L3Harris, or whether a faulty router was installed. L3Harris did not immediately respond to NPR's request for comment.

FAA Administrator Bryan Bedford, who joined Duffy at the briefing, said there was no evidence of anything nefarious or of AI-related issues. The FAA has recently begun rolling out an AI-enhanced software tool called the SMART system as part of its overhaul of the nation's air traffic control system, but Air Space Intelligence, the company behind the tool, rejected speculation it was involved. "The current ground stop is not based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC," the company said on social media.

The aviation system was back online and slowly returning to normal on Saturday morning, but Duffy said delays and cancellations would continue, with the chaos expected to linger for days. Bedford said that based on what airlines are reporting, "they believe that they'll be able to have full schedule integrity by the close of business on Sunday." Duffy told reporters Friday night he expected the system to be operational again heading into the busy Thanksgiving travel period.

For about four hours on Friday, thousands of flights at U.S. airports were grounded in one of the biggest disruptions to the nation's air travel system since the terrorist attacks of September 11, 2001. Nearly 25,000 flights were delayed and more than 9,000 were cancelled on Friday, according to the tracking site FlightAware. The disruption spilled into Saturday morning, with more than 4,000 additional cancellations recorded, amounting to 14% of flights departing the U.S., according to aviation analytics firm Cirium.

Duffy said Friday that air traffic control facilities had experienced intermittent outages of their radar and communications systems beginning earlier that afternoon, and he blamed old switches and old routers for the failures. Homeland Security Secretary Markwayne Mullin, appearing alongside Duffy at the White House, said there was no evidence the problem stemmed from an attack.

Flight boards at airports across the country remained riddled with red cancellation marks on Saturday morning. At Tampa International Airport in Florida, travelers in the main terminal curled up in chairs to sleep. On Friday night, a board at Ronald Reagan Washington National Airport showed dozens of flights delayed into the early morning hours or cancelled. Passengers Erin and Jake Britt boarded a flight to Fort Lauderdale at 3 p.m., only to get off the plane in D.C. at 5:30 p.m. They scrapped their weekend trip and then spent more than nine hours overnight on hold with JetBlue's customer service line seeking reimbursement. "I was setting alarms in 20 minute intervals in case I fell asleep," Erin Britt said.

Joe Romano and Maddie Cabana, who had a cruise departing Orlando on Saturday afternoon, rebooked on Southwest Airlines after their JetBlue flight was cancelled and arrived early Saturday. Suze DiPietro gave up on flying entirely, and her husband drove about four hours from Ocean City, New Jersey, to pick her up in D.C. Other travelers switched to Amtrak trains, though Amtrak's own system suffered a brief outage Friday night.

This was only the second nationwide ground stop since September 11, 2001. The last one, in 2023, shut down all U.S. airports after an outage in the NOTAM system, which alerts pilots and airports to real-time hazards. The FAA later determined that outage was caused when contract workers inadvertently deleted critical files.