PHILADELPHIA, Pa. - A telecommunications failure at a Philadelphia-area air traffic control facility disrupted flights across the Northeast on Monday, temporarily halting incoming traffic at several of the nation's busiest airports and contributing to thousands of delays and hundreds of cancellations nationwide.
The Federal Aviation Administration restricted or stopped traffic at airports including Philadelphia International Airport, Newark Liberty International Airport, John F. Kennedy International Airport and LaGuardia Airport after communications used by air traffic controllers failed.
The disruption became more complicated when authorities discovered that a backup fiber-optic line intended to provide redundancy had been accidentally cut by a construction crew in New Jersey.
FAA Administrator Bryan Bedford said the original telecommunications circuit failed and a replacement circuit also experienced problems. When the system attempted to transition to its backup connection, officials discovered the damaged fiber line.
The combination of failures forced the FAA to reduce or halt incoming traffic while technicians worked to restore reliable communications.
Major Northeast airports affected
At one point Monday, incoming flights were halted at Philadelphia, Newark, JFK and LaGuardia, along with Teterboro Airport and other airports affected by traffic restrictions across the region.
Boston Logan International Airport also temporarily stopped accepting some incoming flights because of additional traffic created by the disruption before those restrictions were lifted.
The FAA began allowing traffic to resume at JFK and LaGuardia as the afternoon progressed, but Bedford said officials could not immediately determine when normal operations would return at Philadelphia and Newark.
The FAA said it would not fully restore incoming traffic until officials were satisfied that the affected airspace could be operated safely.
The outage originated within communications infrastructure associated with the Philadelphia Terminal Radar Approach Control facility, which handles portions of the airspace serving major airports in the region.
Thousands of flights delayed nationwide
The effects quickly spread beyond the airports directly affected by the telecommunications failure.
Nearly 4,000 flights within, into or out of the United States had been delayed Monday, while approximately 500 flights had been canceled, according to flight-tracking data cited by Reuters.
Newark was among the hardest-hit airports. More than 1,000 flights there had been delayed or canceled as the disruption continued.
Flight-tracking service Flightradar24 reported average delays of approximately 112 minutes at Newark during the disruption.
Philadelphia also experienced substantial delays. FlightAware reported that hundreds of flights at Newark and Philadelphia had been delayed, representing more than 20% of scheduled traffic at the two airports at one stage of the outage.
Some flights were diverted to alternate airports as airlines and air traffic controllers adjusted to the restrictions.
Because aircraft and flight crews frequently operate multiple trips during the same day, disruptions at major hubs can continue affecting schedules even after the original ground stops are lifted.
Backup fiber line may take hours to repair
The damaged backup fiber connection could take approximately 13 hours to repair, according to Bedford.
Technicians were also preparing another circuit that could potentially restore communications before repairs to the damaged fiber line were completed.
The incident highlights the importance of redundant telecommunications systems within the national air traffic control network. Backup connections are designed to allow controllers to continue operating when a primary circuit fails, but Monday's outage involved problems affecting both the primary communications system and its backup infrastructure.
Newark and Philadelphia are particularly important transportation hubs. Newark is a major United Airlines hub, while Philadelphia serves as a major hub for American Airlines.
Disruptions at either airport can affect connecting passengers and aircraft schedules throughout the United States and internationally.
Air traffic control infrastructure has faced previous outages
The Philadelphia-area air traffic control system has experienced telecommunications problems before.
In May 2025, the facility responsible for guiding aircraft into and out of Newark experienced several significant communications outages that disrupted operations at the airport.
The FAA subsequently moved forward with additional telecommunications connections and fiber-optic upgrades intended to improve reliability between air traffic control facilities serving the New York and Philadelphia regions.
Congress approved $12.5 billion last year toward modernization of the nation's air traffic control system, including upgrades to aging telecommunications and other infrastructure.
FAA officials have said modernizing those systems will require replacing older equipment while increasing redundancy and reliability across the National Airspace System.
Monday's outage occurred as the New York area was also preparing for heavy international travel associated with the United Nations General Assembly, bringing additional aircraft and government delegations into the region.
What travelers should know
Passengers scheduled to travel through Philadelphia, Newark or other affected Northeast airports should continue checking directly with their airlines before leaving for the airport.
Even where FAA ground stops have been lifted, delays can continue for hours as airlines reposition aircraft, crews and passengers following a major disruption.
Travelers connecting through Newark or Philadelphia could also experience delays on flights originating elsewhere because aircraft scheduled for those routes may have been affected earlier in the day.
The FAA provides real-time information on ground stops, airport delays and other airspace restrictions through its Air Traffic Control System Command Center.
The immediate priority Monday remained restoring stable communications serving Philadelphia and Newark while completing repairs to the damaged backup fiber line.
Traffic had begun moving again at JFK and LaGuardia, but the timing for a full return to normal operations across the Northeast remained uncertain as repairs continued.