The U.S. Transportation Secretary revealed that the nationwide flight groundings last Friday resulted from a malfunction during the upgrade of signal lines from copper to fiber optic.
On 14 Nov 2026, Sean Duffy, U.S. Secretary of Transportation, disclosed that the nationwide flight grounding order, which caused thousands of flight cancellations last Friday, stemmed from technical issues following the copper line upgrade.
Duffy said at a press conference that the government is urgently investigating whether the problem was due to the “incompetence” of the company performing the upgrade or defective equipment. He does not believe the incident was caused by a cyberattack, although investigations continue.
The flight groundings last Friday were the longest since the World Trade Center attacks on 11 Sep 2001, and the resulting disruption is expected to continue for several days.
Duffy revealed that maintenance was underway to replace the copper system with fiber optic lines, conducted by the contractor L3Harris, a technology services company.
The U.S. Transportation Secretary admitted that the U.S. has an incredibly outdated telecommunications system. “The signal lines are so old they are about to be phased out.”
Duffy explained that a router under maintenance began sending excessive data into other air traffic control systems, causing communication problems with aircraft, which led the government to close airspace for safety reasons.
Brian Bedford, Director of the Federal Aviation Administration (FAA), said at the same press conference, “We found no evidence indicating malicious acts and no evidence related to AI.”
All flights were prohibited from taking off from the U.S. mainland for over four hours, starting at 15:54 Eastern Time on Friday.
Flight tracking website FlightAware reported that on Saturday, over 3,500 flights in the U.S. were canceled and more than 2,000 delayed, despite the lifting of the grounding order, due to lingering effects.
Duffy warned that similar problems could recur unless the U.S. Congress approves funding to upgrade the air traffic control infrastructure.
President Donald Trump, the White House, and the U.S. Department of Transportation recently requested $30.1 billion from Congress for this upgrade, but it remains unclear whether Congress will approve the funding before Democrats take control in January.
John Pistole, former head of the Transportation Security Administration (TSA), told BBC News, “The fact they restored the system within four and a half hours is good news, showing system resilience. But what guarantees are there that this won’t happen again tomorrow?”
Source:bbc