FAA lifts nationwide US ground stop after four-hour telecommunications failure

The Federal Aviation Administration lifted a nationwide ground stop on US domestic departures at 2:15 a.m. German time on Saturday, roughly four hours after it halted takeoffs over what the agency called a temporary telecommunications outage affecting all air traffic control centres.

The FAA announced the stop in an online post and said it had acted out of caution. Homeland Security Secretary Markwayne Mullin and Transportation Secretary Sean Duffy confirmed the account at a joint press conference at the White House. The agency later said full functionality had been restored.

Mullin said there was no indication of a malicious attack or a threat. "According to everything we know, it was no cyberattack," he said, adding that nothing could yet be ruled out.

Duffy blamed ageing equipment rather than new systems. "The routers were overloaded," he said, describing an air traffic control system he called extremely outdated. The core problem was that an old analogue system and a new digital system had been run side by side; Mullin said Duffy and the FAA intervened to correct errors, which brought the old system down. "That is why patchwork does not work."

It was the third nationwide halt to US air traffic. Aircraft were first grounded after the attacks of 11 September 2001, and the FAA took the same step in January 2023, when the system used to transmit messages to pilots failed.

Thousands of flights were cancelled and tens of thousands of passengers were left waiting, with long queues at major hubs. Mullin said no lives had been endangered at any point.

In Europe, all flights from Europe to the United States were temporarily suspended overnight, though night-flight restrictions at many airports limited the immediate effect. Eurocontrol withdrew the notice from its website in the early morning and asked airlines to issue delay notices for aircraft unable to depart.

Three flights were diverted back to Germany after taking off from Frankfurt. Only four US-bound flights planned for Saturday were cancelled at Frankfurt, because aircraft could not fly from the US to the city on Friday and were not available as scheduled. At Munich, two flights from the US did not arrive, forcing the cancellation of three planned connections to Charlotte and Houston.

Congress approved 12.5 billion dollars last year to begin modernising the FAA's communications system, and the agency and the White House asked for a further 30.1 billion dollars to fix other defects. In early November Duffy said computer systems dating from the 1980s would be retired by the end of 2028. He hoped for more flights on Saturday, but said normal traffic would take time because aircraft and crews were missing where they were needed.