What Caused the Nationwide Ground Stop? Duffy Points to a Contractor’s Copper-to-Fiber Upgrade

Friday’s nationwide ground stop, which halted departures from U.S. airports for more than four hours, began during routine work on an old Federal Aviation Administration telecommunications line, Transportation Secretary Sean Duffy said on Saturday.

Duffy said the government does not believe it was a cyberattack, though the investigation is still under way, the BBC reported. Thousands of flights were still canceled on Saturday. This is a developing story.

Key points:

• The contractor L3Harris was switching copper wire to fiber at a remote FAA site, Duffy said.
• A router that was being worked on started flooding other air traffic control systems, he said, according to the BBC.
• Officials are still investigating whether the cause was human error or a faulty router.

What Did Officials Say?

Duffy said the routers at these facilities were made in 2001, NPR reported. “It was such an old wire that it was being discontinued,” he said, according to the BBC. The problem caused communication issues with planes, which led the government to shut down the airspace for safety reasons, he explained.

“So what we’re working to determine was whether we had incompetence, meaning was it user error, installator error from L3Harris, or did they install a faulty router?” Duffy said, according to NPR. L3Harris did not immediately respond to NPR’s request for comment.

FAA Administrator Bryan Bedford said at the same news conference: “We see zero evidence of anything nefarious, and zero evidence of anything AI related.”

How Big Was the Disruption?

Nearly 25,000 flights were delayed, and more than 9,000 were canceled on Friday, according to FlightAware data cited by NPR. By Saturday morning, more than 4,000 flights had been canceled, about 14% of flights departing the U.S., according to the aviation data firm Cirium.

Bedford said airlines expect to have “full schedule integrity by the close of business on Sunday.”

Has This Happened Before?

This was only the second nationwide ground stop since the Sept. 11, 2001, attacks. The last one, in January 2023, was caused by a failure of the NOTAM system that sends safety alerts to pilots. The FAA later found that contract workers had accidentally deleted critical files, NPR reported.

What Happens Next?

Duffy warned that a similar outage could happen again unless Congress approves money to upgrade air traffic control systems, the BBC reported. The Trump administration raised its request for air traffic control funding to $50 billion late Friday, CBS News reported.

Former TSA Administrator John Pistole told the BBC that restarting the system in about four and a half hours showed “a resilience in the system,” but added: “What’s to say it’s not going to happen tomorrow?”

If your flight was canceled: check your airline’s app before going to the airport. Under federal rules, if your flight is canceled and you choose not to travel, you are entitled to a full refund.

Sources:

• BBC: Copper wire upgrade caused nationwide flight suspension, US transport secretary says
• NPR: FAA blames Friday’s ground stop on ‘equipment issue’ during telecoms network upgrade
• CBS News: Travelers stranded, flights canceled after ground stop. Here’s what we know
• eCFR: 14 CFR Part 260, airline refund rules

You might also want to read: FAA Halts Departures at Every U.S. Airport After Air Traffic Control Communication Problem