The Federal Aviation Administration halted departures at every US airport on Friday afternoon, in a rare nationwide ground stop. The order took effect at 3.54pm Eastern time, citing extraordinary circumstances and reasons of safety, and it was lifted after more than four hours, with Transportation Secretary Sean Duffy saying airspace reopened at 8.15pm. Aircraft already in the air were allowed to continue and land, and international arrivals were handled case by case. Reports differ on whether it lasted more than four or about five hours, and on whether it was the second or third such nationwide stop since the September 2001 attacks.
The cause was a telecommunications failure affecting the air route traffic control centres that manage flights across the country. Duffy said switches and routers became overloaded with data and failed, with no total loss of communications or radar, and officials acknowledged that new technology added to the system overloaded older parts, causing intermittent communication and radar gaps. Homeland Security Secretary Markwayne Mullin said there was no cyberattack and the public was never in danger. The disruption came in the same week that the administration rolled out an AI-powered tool for air traffic controllers, and it is not clear whether the two are connected. A September government audit report had warned of ageing copper cables dating to the 1960s and of poorly scheduled system changes that overlapped and overwhelmed the network.
The scale was large. About 11,000 flights carrying more than 1.5 million passengers were scheduled to depart after 4pm. By 7.05pm at least 827 flights had been diverted, 670 of them back to their departure airports, and a flight-tracking service counted more than 4,700 cancellations and about 10,000 delays on Friday, with about 700 cancellations already made for Saturday. Washington Reagan National and Los Angeles were among the affected airports.
Duffy said flights would resume slowly, depending on the availability of pilots and flight attendants, that it would take some time to return to capacity and that he expects normal operations by Thanksgiving, which begins in under two weeks. He called for $50 billion in upgrades to the air traffic control system. Aviation specialists said recovery would take more than a day because aircraft and crews must be rescheduled across interconnected hubs, and one questioned why backup systems did not take over at once. Experts warn the ageing system remains vulnerable to further disruption.
