Cable cut triggers ATC outage and mass flight disruption across the US Northeast

A telecommunications circuit that serves the facility handling Philadelphia International Airport failed Monday afternoon. Ground stops followed at several of the busiest airports in the northeastern United States, and the disruption spread across the country's air travel network.

Officials said the failure exposed a second problem: a backup fibre line in New Jersey had been severed. U.S. Transportation Secretary Sean Duffy said on X that a construction crew working for Amtrak cut the cable by mistake.

Ground stops were imposed at New York-JFK, LaGuardia, Newark and Philadelphia, with congestion reaching as far as Boston. Figures cited as of 4 p.m. put roughly 5,000 delayed flights into, out of or inside the United States and more than 800 cancellations, though not all were tied directly to the outage. Newark was hit hardest, with close to half of its Monday schedule cancelled.

Around 3 p.m., Duffy said operations were restarting at Philadelphia and LaGuardia. Arrivals at JFK, Newark and Teterboro Airport in New Jersey were still on hold at that point.

The FAA advised passengers to confirm their flight status with their carrier.

FAA Administrator Bryan Bedford told reporters the circuit that first went down is among the older L3 Verizon circuits the agency is replacing under a multibillion-dollar programme.