Updated 6:07 p.m. ET Friday: The FAA said the nationwide ground stop remains in effect and that flights will be allowed to depart as en route facilities recover, through coordination with the command center. A 5:46 p.m. ET advisory cites a communications failure and lists the restriction through 11 p.m. ET, when the agency expects to issue another update. It has not said when departures will fully resume. Its operations plan calls for a “tiered approach” to releasing traffic as conditions allow. Homeland Security Secretary Markwayne Mullin said earlier there was no indication of an attack. FlightAware counted more than 10,000 delays and about 2,000 cancellations today among flights within, into or out of the United States.
The Federal Aviation Administration stopped every departing flight in the United States on Friday afternoon after a communications failure hit the regional centers that guide planes between airports. It is only the third nationwide ground stop in 25 years and the first since January 2023.
The halt turned an IT failure into a physical one, with planes, crews and passengers stuck wherever they were when the order came down on a Friday afternoon. It also followed a Microsoft 365 outage that knocked out Outlook and other services for businesses worldwide, though Homeland Security Secretary Markwayne Mullin told reporters there was no reason to connect the two.
The order went out at 3:54 p.m. ET in an advisory from the FAA’s Air Traffic Control System Command Center, which cited “extraordinary circumstances and for reasons of safety.” “All departing traffic should remain ground stopped until further notice,” the advisory said. Inbound international flights are being handled case by case. As of 6:07 p.m. ET Friday, the stop remained in effect. The FAA said it would allow flights to depart as en route facilities recover, but it had not said when the order would be lifted in full.
Transportation Secretary Sean Duffy said on X the stop followed “a communication issue impacting all Air Route Traffic Control Centers,” and that FAA technicians were investigating. An FAA statement to TechCrunch cited “communication issues impacting multiple Air Route Traffic Control Centers,” the facilities that handle high-altitude traffic between airports. Before the national order, centers including Boston, Chicago and New York had reported radio frequency outages, WIRED reported, and the FAA had already halted traffic in Chicago, according to SecurityWeek. A later FAA advisory extended flight plan drop times to 240 minutes for all en route centers “due to nationwide comms failure.”
Just after 5 p.m. ET, the agency called it a temporary telecommunications outage in a post on X and said every flight had been accounted for.
A root cause has not been identified. The FAA’s latest advisory cites a communications failure. Bloomberg News reported shortly after 5 p.m. ET that the FBI is examining whether a software update triggered the outage. Officials have not confirmed the report. Speaking at the White House, Mullin said there was no indication of an attack and that he could not rule anything out, the BBC reported. “We have not discussed any time frame,” he said. “It’s going to take some time.”
The backlog built quickly. By about 6 p.m. ET, FlightAware counted more than 10,000 delays and about 2,000 cancellations today among flights within, into or out of the U.S. Flightradar24 tracked about 3,100 airborne aircraft headed for U.S. airports as the order took hold. Planes in the air could still land, but a passenger at Los Angeles International Airport told the BBC that newly landed flights were not being allowed to move from the tarmac to the gates.
Airlines told customers to wait. United said on its website that it was holding planes from taking off and that flights already in the air would continue, and Delta said its flights were “currently being impacted by an ATC-mandated nationwide ground stop,” Business Insider reported. American Airlines told customers on X its teams were ready to move them “as quickly as possible once the FAA’s nationwide ground stop is lifted.”
A prolonged stop would take days to unwind. Michael McCormick, an Embry-Riddle Aeronautical University professor and former air traffic controller, told WIRED that an outage lasting more than a couple of hours would leave aircraft and crews in the wrong places. “It would take days to get up and back running normally,” he said. Axios aviation reporter Alex Fitzpatrick wrote that airports could run out of gates for the thousands of flights already airborne.
The 2023 stop lasted under two hours. It followed a failure of the FAA’s Notice to Air Missions system, which the FAA’s preliminary findings traced to contract personnel who “unintentionally deleted files while working to correct synchronization between the live primary database and a backup database.” Before that, the FAA had grounded all flights only on Sept. 11, 2001. “Right now all it takes is for one system to go out, and it affects a wide region at once,” Susan Hotle, a Virginia Tech transportation engineering professor who worked at the FAA, told WIRED.
The failure also comes during a busy stretch of technology changes at the agency, which this week expanded SMART, an AI tool that advises controllers on congestion, nationwide. WIRED said there is no evidence the ground stop is related to that tool, though Mullin said officials were looking at whether it played a role, Business Insider reported. Last week, WebProNews reported that the FAA is replacing floppy drives in its systems.
For now, Mullin said, the focus is on restoring communications and getting every flight on the ground. As of 6:07 p.m. ET Friday, the nationwide stop remained in effect, and the FAA said it would release traffic in stages as conditions allow.
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