Radar failure grounds thousands of flights across U.S. Northeast

Thousands of flights were cancelled or delayed across the northeastern United States on Monday (Sept. 21) after an equipment failure disrupted air traffic control operations, affecting major airports in New York, New Jersey and Philadelphia.

The disruption stemmed from a communications failure at a key Federal Aviation Administration (FAA) facility in Philadelphia that left air traffic controllers without radar or communications capabilities.

According to FAA Administrator Bryan Bedford, a circuit on the facility’s primary communications line failed Monday morning.

When the system attempted to switch to its backup, officials discovered that the backup fibre-optic cable had been damaged by a construction crew in New Jersey, Reuters reports.

The outage affected flights at several of the region’s busiest airports, including New York’s John F. Kennedy International Airport and LaGuardia Airport, Newark Liberty International Airport and Philadelphia International Airport. Boston was also among the airports experiencing disruptions.

According to FlightAware, a flight-tracking website, more than 5,600 U.S. flights were delayed or cancelled, including 1,200 flights at ⁠the three New York-area airports.

The issue also diverted more than 100 flights to other airports.

Flights resume, but expect delays

By Monday evening, flights were beginning to resume at the affected airports, although significant delays were expected to continue throughout the day.

The FAA advised passengers to check their flight status before travelling to the airport, while some airlines offered customers the option to change their flights without additional fees.

The disruption came at a particularly busy time for New York, on the eve of the United Nations General Assembly, which is expected to bring more than 130 officials and world leaders to the city, including Prime Minister Mark Carney, who will reportedly miss an event due to flight issues. 

U.S. Transportation Secretary Sean Duffy said the incident “underscores the need for additional funding” to modernize the country’s “ageing infrastructure.”

Telecommunications company Verizon said it was “actively working” to repair the damaged cable and restore connectivity.

The Philadelphia-area facility has been linked to previous air traffic disruptions. Technical and staffing problems at the same FAA operation contributed to widespread delays and cancellations at Newark Liberty International Airport in the spring of 2025.

Regional air traffic control centres typically rely on primary and backup lines to transmit radar and communications data.

Monday’s outage occurred when the primary circuit failed and the backup connection was found to have been severed.

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