A router undergoing replacement and decades-old copper cables are at the center of the investigation seeking to explain why U.S. airspace was paralyzed on Friday, November 13, in what became the third national air closure in modern history of the United States.
The Federal Aviation Administration (FAA) ordered a complete suspension of all departing flights at 3:54 PM Eastern Time after detecting that radio frequencies and radar systems were "interrupting and rebooting" simultaneously across multiple control centers. The instability began approximately 18 minutes earlier and affected 17 of the 22 regional centers in the country. The shutdown lasted for more than four and a half hours.
The Secretary of Transportation, Sean Duffy, pointed to the contractor L3Harris Technologies as the main focus of the investigation this Sunday. The company was performing routine maintenance work at a remote facility in El Dorado, Arkansas, replacing old copper lines with fiber optics, when a router began flooding the network with over 1,000 connection attempts every four to five seconds, overloading equipment that included Cisco routers manufactured between 2001 and 2006.
"What did L3Harris do? Did they make mistakes? They own this network. They are our primary contractor. I cannot turn to another company. They are responsible. Or was it a faulty router? We're going to find out. And, frankly, we are going to demand accountability," Duffy stated to the press.
Duffy also revealed a second installation in Amarillo, Texas, where similar work had been carried out weeks earlier, and its potential connection to Friday's collapse is still under investigation. Both the FAA and the FBI are on-site alongside L3Harris to determine the root cause.
The FAA director, Bryan Bedford, explained why the agency made the extraordinary decision to suspend all departures: "If it had been just one facility, we would have simply worked to resolve it. But when we saw the problem spreading to two, three, 10, and 17 facilities, we began to realize that something much larger was happening."
The authorities explicitly ruled out a cyberattack. Bedford stated that "we do not see any evidence of malicious activity or any indication that it is related to artificial intelligence."
The air chaos extended over the weekend: Saturday closed with 6,695 cancellations and 9,011 delays nationwide. On Sunday, FlightAware reported still 1,454 canceled flights and 2,258 delays early in the morning. Among those affected are flights to Cuba: American Airlines flight AA2705 to Havana was canceled on Saturday and rescheduled with a delay of more than three hours, while World Atlantic connections to Havana and Camagüey faced delays of between two and two and a half hours.
The incident reopened the debate on the obsolescence of U.S. air traffic infrastructure. A Government Accountability Office report published in September warned that over 75% of the 138 FAA systems evaluated were unsustainable or potentially unsustainable, with equipment still relying on floppy disks and interfaces from the 1980s.
Duffy acknowledged that about 30% of the copper cables in the network have not yet been replaced by fiber optics, and he urged Congress for a total investment of $50 billion to modernize the system. "More incidents like this are going to occur. There will be more interruptions unless the American people and Congress tell us to build the new system," he warned.
In the interview he gave this Sunday to the program "Face the Nation," Duffy estimated that airspace should operate at full capacity before the end of the day or by Monday, just in time for Thanksgiving week, one of the busiest travel periods of the year in the United States.
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