Signage outside the L3Harris MAS facility in Mirabel, Quebec, Canada, on Wednesday, May 13, 2026. Photographer: Andrej Ivanov/Bloomberg via Getty Images
Transportation Secretary Sean Duffy said Saturday that a technical problem may have developed while FAA contractor L3Harris was upgrading a telecommunications line, triggering Friday’s nationwide ground stop.
What they're saying:
"At least one of our remote FAA locations, a contractor was doing routine maintenance to switch telecommunication lines from old copper wire, and they were bringing it over to fiber. That contractor that does the work for us is L3Harris. They're a legacy provider. They've been working for the FAA for over 20 years. … The network that we use at the FAA to control the airspace — L3Harris actually owns that network," Duffy said Saturday.
Dig deeper:
Duffy said a router at the location became overwhelmed by a surge of data as the contractor replaced copper lines with fiber-optic cables. The disruption then spread to routers at other FAA air traffic control facilities across the country.
RELATED: US flights to return to normal Sunday after ground stop canceled 1,000s of flights, FAA says
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FAA ground stop: Duffy blames contractor & old equipment
BREAKING: Transportation Secretary Sean Duffy says investigators are looking into whether a contractor's installation error or a faulty router caused a failure in the nation's air traffic control system. The issue surfaced during an upgrade from copper to fiber connections, when a router being replaced began overwhelming other routers across the network. Officials are now investigating whether the disruption was caused by a contractor mistake or an equipment malfunction.
The other side:
L3Harris told Fox News Digital in a statement that it was assisting with the FAA’s investigation.
"L3Harris has been modernizing the communications infrastructure supporting the National Airspace System in close coordination with the FAA," the company wrote. "With safety and reliability as our highest priorities, L3Harris, together with its telco partners and the FAA, has completed more than 70% of the planned airspace communications conversion from legacy copper wires to a fiber optic system."
The company said it was "supporting the FAA in its investigation to understand the conditions that led to the Nov. 13 ground stop of our nation’s air travel," adding that it "takes the nationwide ground stop and its impact on travelers, airlines and air traffic operations seriously."
Why you should care:
Duffy said the FAA and Transportation Department were investigating whether the disruption resulted from an installation mistake or a defective router.
"What we're working to determine was whether we had incompetence — meaning was it user error or installation error from L3Harris — or did they install a faulty router? We haven't determined what the fault was. Was it the router, or were they not doing great work for us at L3Harris," he said.
RELATED: Hochul calls for Transportation Secretary Duffy's resignation, firing after FAA ground stop
Asked whether the government’s lead systems investigator oversaw the work that preceded the network failure, Duffy pointed to the contractor.
"So this is L3Harris," he replied.
"It's our legacy telecom network. It's owned by L3Harris. With our new architecture, with the money that we're requesting, we will work with the greatest telecom companies in the world, which will be AT&T, Verizon and Lumen. They're all working with us on the new architecture," Duffy said. "But in the meantime, until I can build that, I'm stuck with L3Harris, who owns this network."
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Airlines recovering after nationwide ground stop
Thousands of flights were canceled across the U.S. on Saturday as airlines worked to get operations back on track following a nationwide ground stop. The disruption left travelers scrambling to find available seats and caused ripple effects across the global travel network. Livenow’s Austin Westfall is joined by Katy Nastro of flighty to discuss the widespread travel disruptions.
The backstory:
L3Harris has worked on FAA telecommunications since 2002 and supplies technology to a range of government customers.
According to its website, the company provides advanced targeting and ordnance systems to the Defense Department, along with weapons-related components and electronic systems for military use. Its products include ignition safety devices, proximity sensors and electronic fuzes.
L3Harris is also one of the U.S. military’s largest suppliers of tactical radios and other communications equipment.
The publicly traded company’s major institutional shareholders include BlackRock, with a 10.21% stake; State Street, with 5.1%; and Vanguard, with just under 12% held through Vanguard Capital Management LLC and Vanguard Portfolio Management LLC.
L3Harris reported $6.1 billion in revenue for the third quarter of 2026, according to its quarterly earnings report.
The company was established in 2019 through the merger of Harris Corporation and L3 Technologies.
The FAA and Transportation Department did not immediately respond to requests for comment from FOX Business.
The Source: FOX Business contributed to this report. Information in this story came from Transportation Secretary Sean Duffy’s Saturday news conference, an L3Harris statement provided to Fox News Digital, the company’s website and its third-quarter 2026 earnings report. FOX Business also sought comment from the FAA and Transportation Department, which did not immediately respond. This story was reported from Los Angeles.