Construction crew severs backup cable, knocking out Northeast air traffic control for hours

A construction crew working in New Jersey accidentally severed a fiber-optic cable Monday morning, and what should have been a routine switch to backup communications instead revealed a second failure — leaving the FAA's Philadelphia TRACON facility without radar or communications for hours and bringing commercial air travel across the Northeast to a near-standstill.

By Monday evening, Transportation Secretary Sean Duffy announced that telecom lines had been repaired and operations were resuming at all affected airports. The toll on flight schedules, however, proved severe: 6abc reported that more than 1,000 flights were canceled across the country and upward of 6,000 were delayed, with Newark Liberty International and Philadelphia International Airport bearing the worst of it.

It will take some time to clear all existing delays, so please check with your airline for the latest information.— Sean Duffy, Transportation Secretary

The sequence of failures began around 9:45 a.m. Monday, when a construction crew severed a Verizon fiber-optic cable in New Jersey, according to New Jersey Transit, which said the crew was working about 10 feet away from utility line markings. Earlier that morning, the FAA's Philadelphia TRACON facility — which integrates radar approach control and air traffic control for a dense stretch of Northeast airspace — had already lost its primary communications circuit. When the system tried to switch to the backup line, workers discovered that line had also been cut, according to CNN.

The result was ground stops at five airports: Newark Liberty International, Philadelphia International, LaGuardia, John F. Kennedy International, and Teterboro. No commercial flights landed at Newark from approximately 9:40 a.m. to just after 5:20 p.m. local time, a span documented by flight-tracking site Flightradar24, as cited by 6abc. More than 300 flights at Newark had been canceled as of Monday evening — more cancellations than any other airport in the world that day, according to FlightAware data cited by CNN. Cancellations at Philadelphia International also topped 200 flights, both arrivals and departures.

Yeah, man, nothing works. People are getting out, but it's slow going.— Air traffic controller, Philadelphia International Airport

A blame dispute emerged over which construction crew was responsible. Earlier Monday, Duffy said an Amtrak construction crew was at fault. Amtrak, however, pointed to a New Jersey Transit crew working between Newark and New Brunswick, New Jersey, according to 6abc. NJ Transit said in a statement to CNN that it would continue working with Verizon and the contractor as the circumstances are investigated. Verizon, for its part, said its cables were properly placed and that contractors are responsible for calling for correct markings before digging.

The contractors are responsible for calling for the correct markings and the actual work. Our cables were properly placed.— Verizon, statement

The failed primary circuit had already been scheduled for replacement as part of a broader overhaul of the nation's air traffic control system, according to both CNN and 6abc. FAA Administrator Bryan Bedford told CNN affiliate WUSA that officials discovered the break in the backup fiber only when the system switched to backup mode. Earlier in the day, an attempt to fix the primary connection by installing a new circuit had not worked, leaving operations halted at Philadelphia and Newark for hours before the eventual repair.

This is why we're asking for budget to replace all of this stuff… We're pulling copper up and putting fiber down, but it's the same data architecture that we've had for 50 years.— Bryan Bedford, FAA Administrator

The Philadelphia TRACON facility has a recent history of outages. A roughly two-second radio outage struck the facility last May, coming just days after a separate outage had triggered a ground stop for flights bound for Newark. The facility had moved from Long Island to Philadelphia the previous summer, and the FAA had insisted upgrades would prevent further disruptions. After last year's outages, the Department of Transportation introduced a new fiber-optic cable between Philadelphia and New York specifically to improve telecommunications at the facility, according to CNN.

This incident underscores the need for additional funding to modernize aging infrastructure and prevent disruptions like this in the future.— Sean Duffy, Transportation Secretary

The timing compounded the disruption's reach. Canadian Prime Minister Mark Carney's arrival in New York City was delayed because of the system failure, causing him to miss a previously scheduled summit, his office told CNN, even as world leaders were converging on New York for the United Nations General Assembly beginning Tuesday.

Philadelphia's role as a major American Airlines hub amplified the knock-on effects across the network, according to thetraveler.org. When one flight is canceled, the aircraft it was meant to operate next sits out of position, setting off a chain of disrupted departures that persists long after the original problem is resolved. According to thetraveler.org, delays at Philadelphia climbed past three hours at certain points in the recovery window, and their effects lingered well after service resumed.

Also Monday, the FAA began testing a new AI-assisted computer system designed to help air traffic controllers predict schedule conflicts and weather issues. According to 6abc, the system is being piloted exclusively in the Washington, D.C., area at this stage and showed no connection to the outages.

These are issues that aren't new to us. This is not a new problem. It's an old system that we were stuck working with.— Sean Duffy, Transportation Secretary

Why it matters — The outage exposed how a single construction mistake can cascade through aging, redundancy-thin infrastructure to ground flights at five major airports simultaneously — and reignites a long-running debate over whether the FAA has the funding to modernize before the next failure.

Sources differ on Which construction crew severed the fiber-optic cable: An Amtrak construction crew (later walked back) (6abc.com (citing Duffy's earlier statement)) vs A New Jersey Transit construction crew working between Newark and New Brunswick, NJ (cnn.com (citing NJ Transit statement))

Reported by 6abc.com, cnn.com, thetraveler.org