FAA telecom upgrade triggers nationwide flight ground stop

A routine upgrade of an aging Federal Aviation Administration telecommunications line triggered a nationwide ground stop Friday, halting departures for more than four hours and leaving thousands of flights canceled, Transportation Secretary Sean Duffy said Saturday.

Contractor L3Harris was replacing copper wire with fiber at a remote FAA location when an error caused a router to flood other parts of the air traffic control network, disrupting communications with planes, Duffy said. Officials stopped departures for safety reasons while they worked to restore the system.

The FAA is investigating whether the problem stemmed from an installation error or faulty equipment. “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. L3Harris did not immediately respond to NPR’s request for comment.

Officials said they had found no indication of an attack. FAA Administrator Bryan Bedford told the briefing: “We see zero evidence of anything nefarious, and zero evidence of anything AI related.” Duffy said the investigation was continuing.

No flights were allowed to take off from the continental United States for more than four hours beginning at 3:54 p.m. Eastern on Friday, the BBC reported. Some international departures were allowed, apparently to free space at airports, while some passengers remained aboard planes that could neither take off nor return to gates, according to the BBC.

FlightAware figures cited by NPR showed nearly 25,000 flights delayed and more than 9,000 canceled Friday. Saturday’s disruption continued: the BBC cited FlightAware figures of more than 3,500 cancellations and more than 2,000 delays, while NPR reported more than 4,000 Saturday cancellations. NPR, citing aviation analytics firm Cirium, said cancellations represented 14% of flights departing the United States.

The aviation system was back online Saturday morning, but the backlog was expected to take days to clear. Bedford said airlines believed they could restore their full schedules by the close of business Sunday. Duffy said Friday night that he expected operations to recover as Thanksgiving travel intensified.

For travelers, the disruption meant missed plans and long waits for help. Erin and Jake Britt, whose flight from Washington, D.C., to Fort Lauderdale never departed, canceled their weekend trip and spent more than nine hours waiting on a JetBlue customer service line for reimbursement, NPR reported. “No one was prepared,” Erin Britt said.

Duffy described the FAA’s telecommunications equipment as exceptionally old. According to NPR, he said routers at the facilities were manufactured in 2001. “Virtually every single institution in America has gone from copper to fiber, from analog to digital,” he said.

Duffy warned that similar failures could recur without congressional approval for air traffic control upgrades. President Donald Trump has requested $30.1 billion for the work, the BBC reported.

The ground stop was only the second nationwide suspension since flights were halted after the Sept. 11, 2001, attacks. NPR reported that the previous one, in 2023, followed an outage of the system that alerts pilots to hazards; the FAA later attributed that outage to contract workers inadvertently deleting critical files.