Transportation Secretary Sean Duffy said Sunday that two routers from FAA facilities in Texas and Arkansas are being tested as investigators work to determine whether defective equipment or an installation issue caused the country’s longest nationwide flight ground stop in 25 years.
Duffy told Fox News Sunday that investigators have found no evidence of a foreign cyberattack. The FBI and other federal law enforcement agencies are still involved in the investigation, he said.
“We think it was the installation or the router that was the bad actor,” Duffy said, adding that officials would keep investigating with federal partners if new evidence emerged.
In a post on X, Duffy said contractor L3Harris had secured the routers from remote FAA facilities in Texas and Arkansas. The company is carrying out what he called “deep diagnostics testing” at its Florida headquarters, with engineers from the FAA, Juniper and Cisco taking part.
The investigation comes after Friday’s nationwide ground stop, which halted air traffic for more than four hours and contributed to disruption for about 15,000 flights over Friday and Saturday.
Delays and cancellations continued Sunday. By noon ET, 3,798 flights within, into or out of the United States had been delayed, while 1,638 had been canceled, according to FlightAware. Atlanta’s Hartsfield-Jackson International Airport recorded 376 delays. Dallas Fort Worth International Airport had 363 delays and 195 cancellations.
The disruption happened while L3Harris was replacing aging copper wiring in the FAA communications system with fiber-optic technology. The work caused intermittent communication problems and radar gaps, leading officials to halt flights nationwide.
Duffy said President Donald Trump brought federal officials together by phone on Friday as the administration looked into whether the disruption might have involved deliberate interference.
“Was anyone seeing footprints? Was anyone hearing chatter? Was this a cyberattack from a foreign nation?” Duffy recalled Trump asking. “We have no indication that that was at play here,” he said.
Duffy defended the decision to ground flights, saying passenger safety comes first when problems arise in the FAA’s communications network.
“When we have inconsistencies in our network, we’re going to shut it down,” he said.
He also said the agency’s communications infrastructure remains outdated, even as work to replace copper wiring with fiber-optic technology continues. “We’re still using an old 1980 architecture for telecom,” Duffy said. “I need a brand-new telecom system.”
AT&T, Verizon and Lumen are prepared to help build a replacement network, Duffy said, but moving ahead would require additional funding from Congress.
Democrats in Congress have questioned the request, arguing that the administration has yet to spend billions already allocated for air traffic control modernization. Duffy said that money was designated for specific improvements, including radar, radios and electronic flight strips, not for a new communications network.
FAA Administrator Bryan Bedford said Saturday that “the worst is behind us” and predicted air travel would return to normal by the end of Sunday.
The ground stop was the first nationwide shutdown of its kind since January 2023 and only the second since the Sept. 11, 2001, terrorist attacks.
