The U.S. aviation regulator, the FAA, banned takeoffs in the United States on Friday, November 13, after a failure of communications systems. This highly unusual measure led to the cancellation of 6,000 flights and affected hundreds of thousands of passengers.
Sean Duffy, the Transportation secretary, said communications and radar were then operating only intermittently at several control centers. Air traffic controllers could not immediately see where the aircraft were.
Flights resumed on Saturday after several hours in which all takeoffs were suspended because of this major outage.
He ruled out a cyberattack as well as any link to the global outage at Microsoft.
When the ground stop was issued, 4,042 flights were en route to U.S. airports, according to FlightRadar.
An FAA statement, cited by several U.S. media outlets including CNN, referred to exceptional circumstances and safety reasons, without further detail.
The text ordered that air traffic remain suspended until further notice and that international flights be handled on a case-by-case basis.
The U.S. secretary of Homeland Security then responded: there is no indication that a threat to the United States prompted these instructions from the regulator.
Sean Duffy said on Friday that technicians were investigating the problem.
The episode is neither a first nor a surprise. It comes a few weeks after a new report on the obsolescence of air traffic control tools and the announcement of a historic modernization. This latest incident is the consequence of keeping those obsolete tools in service.
The GAO finds these systems impractical for controllers, who must search for, retrieve, and display information through inefficient operations that are nonetheless necessary to their dealings with pilots.
The same report describes communications between U.S. controllers and commercial aircraft as incredibly insecure. A senator warned that this technology can be intercepted, spoofed, and jammed, and that hackers as well as foreign governments can exploit these vulnerabilities to disrupt traffic or even put passengers in danger.
The report appeared 24 hours before another incident that caused a telecommunications outage at several airports on the East Coast. In 2025, two communications failures had already affected flights at Newark, one of the three major airports serving New York.
The announced modernization relies on camera systems and displays intended to give controllers a 360° view of operations, runways, taxiways, and nearby airspace. E-IDS, for its part, aims to turn control towers into digital towers.