Flights are taking off again across the United States after the Federal Aviation Administration lifted a rare nationwide ground stop late on Friday, November 13. A failure in air traffic control communications had halted departures for more than four hours, and the effects spread across the US network and into Canada.
The FAA ordered the stop at 20:54 UTC (3:54 p.m. Eastern), citing “extraordinary circumstances” and “reasons of safety.” Transportation Secretary Sean Duffy said a communication issue had hit all 22 Air Route Traffic Control Centers, which manage aircraft at cruising altitude across the country. Planes that were already airborne were allowed to land, but no new flights could depart. International flights were handled on a case-by-case basis.
According to Flightradar24, 4,042 flights were in the air heading to US airports when the order was issued.
Overloaded routers blamed
Duffy later said network switches and routers had become overloaded and shut down after they started sending inconsistent data. He said controllers did not lose all radar or all communications, but the data was too unstable to keep flights moving safely. Duffy blamed the outage on the FAA’s aging air traffic control system and warned that more incidents like this could happen unless it is upgraded.
Homeland Security Secretary Markwayne Mullin said there was no sign the outage was caused by a threat against the US. Air Space Intelligence, the company that supplies the FAA’s new AI-based air traffic management system, said its technology was not responsible.
Thousands of flights canceled
According to FlightAware, more than 25,000 flights within, into or out of the US were delayed on Friday, and more than 6,600 were canceled. Airports in Toronto, Montreal, Vancouver, Calgary, Edmonton and Ottawa also reported cancellations on US routes.
Delta Air Lines and United Airlines both said they had resumed operations after the stop was lifted. Even so, more delays and cancellations are expected through the weekend while airlines get aircraft and crews back where they need to be. Passengers flying to, from or within the US should check their flight status with their airline before going to the airport.
Only the third since 9/11
Nationwide ground stops are extremely rare. The last one was in January 2023, when a failure in an FAA computer system grounded flights for about 90 minutes. Before that, the FAA closed all US airspace after the attacks of September 11, 2001.
