The Federal Aviation Administration halted all departing flights across the country Friday afternoon, Nov. 13, after a communication issue hit the nation's air traffic control system.

The ground stop took effect at 2:54 p.m. Central Time, according to an advisory from the FAA's Air Traffic Control System Command Center, as News On 6 reported. The order applied to every U.S. airport, including Will Rogers International Airport in Oklahoma City.

Stacey Hamm with Will Rogers International Airport said airport officials were monitoring the situation and would provide more information as it became available, according to KOCO. The airport's website listed three flights as delayed, with some delays also showing for inbound flights.

The total number of flights affected at Will Rogers had not been confirmed.

What caused the ground stop

The FAA said a communication issue was affecting all Air Route Traffic Control Centers, the 22 facilities that manage aircraft flying above 18,000 feet across U.S. airspace, according to ABC News. FAA technicians were investigating the disruption.

Transportation Secretary Sean Duffy described the cause in a post on X, saying it was "due a communication issue impacting all Air Route Traffic Control Centers," ABC News reported.

Homeland Security Secretary Markwayne Mullin, the former Oklahoma Republican senator confirmed to lead the department in March, spoke to reporters at the White House. Mullin said there was "no indication as of yet" of anything "nefarious" behind the outage, according to NBC News.

The cause remains under investigation.

Mullin said the outage had affected the clarity of communications with aircraft, but some communication systems remained operational, News On 6 reported. He said investigators had not determined the cause and declined to speculate about whether a cyberattack could be responsible.

When asked whether the outage could be connected to the FAA's reported rollout of a new artificial intelligence air traffic control system, Mullin said federal agencies were examining that possibility, News On 6 reported.

Nationwide impact

As of about 3:45 p.m. Nov. 13, FlightAware reported 7,884 delays and 340 cancellations for flights within, into or out of the United States, according to News On 6.

Roughly 3,000 flights were already airborne when the order came down, Fox Weather reported. International flights arriving in the U.S. were being handled on a case-by-case basis, according to the FAA advisory.

The FAA's advisory listed 10 p.m. Central Time on Nov. 13 as the estimated end of the ground stop, but the agency directed departing aircraft to remain grounded "until further notice," News On 6 reported. The FAA had not confirmed when flights would resume.

A rare order

Nationwide ground stops are extremely rare. The last one came Jan. 11, 2023, when a failure in the FAA's Notice to Air Missions system, known as NOTAM, halted domestic departures for about 90 minutes. That disruption caused more than 10,000 delays and over 1,300 cancellations, News On 6 reported.

Travelers flying out of Will Rogers can check flight status at the airport's website, flyokc.com.