FAA orders nationwide ground stop on all departing US flights

The Federal Aviation Administration has ordered a nationwide ground stop on all departing flights in the United States, citing "extraordinary circumstances" and "reasons of safety". The order was issued at 3:54 p.m. ET on Friday, 13 November, and keeps departing traffic on the ground until further notice.

The FAA said the stop followed communication problems affecting several Air Route Traffic Control Centers. Outages were reported across the country, knocking out air traffic control radars and radio frequencies at the same time, and controllers have no clear picture of the cause. The FAA says technicians are investigating and will provide immediate updates.

Homeland Security Secretary Markwayne Mullin said there was "no indication as of yet" that anything "nefarious" was behind the failure. Officials are also examining whether a new AI-supported air traffic control system contributed. ASI, the company behind that system, said the stop was "not based on or a result of the SMART system". The FAA is expanding SMART, an $875 million tool, to help manage air traffic across the national airspace, and says it will not affect air safety.

Airlines are feeling the impact. United said flights already in the air will continue, but no new domestic departures will leave while the stop is in place, and inbound international flights are being handled case by case. By 5:00 p.m. ET, FlightAware counted more than 9,000 flights delayed into, within or out of the US and over 440 cancellations. Reagan Washington National Airport is reported to be at capacity and Chicago O'Hare is nearing it, which leaves little room to park aircraft if diversions increase.

Nationwide ground stops are very rare. The last comparable events were after the September 11 attacks and in January 2023, when a failure in the Notice to Air Missions system grounded flights across the country. The story is still developing, and sources describe the cause differently.