FAA Halts Newark and Philadelphia Flights After Radio Failure as GAO Warns of Cyber Threats

The FAA attributed the ground stop to issues with some frequencies at Philadelphia TRACON, which guides planes in and out of Newark and Philadelphia. CNBC reported that the disruption stemmed from an equipment outage. The agency has not said what caused the outage, The Guardian reported. A ground stop was ordered at about 10 a.m. for Newark, Philadelphia and Teterboro, with some radio frequencies affected until early afternoon, according to The Guardian.

About 250 flights in and out of Newark were delayed, more than a fifth of the day’s schedule, according to FlightAware. Flightradar24 data showed 67 flights bound for Newark had been diverted as of about 1 p.m. ET, including international flights returning from Iceland, Greece, Spain and France. United Airlines, which operates its busiest international hub at Newark, waived flight change fees for affected travelers.

The disruption coincided with the publication of a Government Accountability Office report that found the FAA had not completed risk assessments or updated security documentation for threats including spoofing, jamming and other attacks on the radio spectrum, The Guardian reported. According to the report, the FAA also lacks a real-time system to detect all such threats, meaning it generally can only investigate incidents after they are reported. Investigators warned that a hacker could send fraudulent messages, such as false cancellations of flight clearances, to aircraft, potentially causing delays, disrupting airspace or creating safety risks. Two systems used to send text messages to aircraft predate modern cybersecurity standards and lack common protections such as encryption, the report said.

Senator Ron Wyden of Oregon said, “The FAA’s failure to require the aviation industry to use secure communications is a major threat to US national security, to our economy and the safety of the flying public.” He added: “The FAA needs to issue new standards, as soon as possible, to protect the security of airline communications.” Wyden, who sits on the Senate intelligence committee, also said the GAO report revealed that air traffic controllers’ communications technology “is incredibly insecure, can be intercepted, impersonated, and jammed, and that hackers and foreign governments can exploit these vulnerabilities to disrupt air travel and even put passengers at risk.”

The GAO made nine recommendations, including formal risk assessments for seven of eight reviewed systems, continuous monitoring for interference, spoofing and jamming, and formal guidance on information sharing. The Department of Transportation, replying for the FAA, agreed with all nine.

Monday’s disruption is the latest in a series of problems around Newark. In April 2025, an outage blanked controllers’ screens for roughly 60 to 90 seconds and cut their contact with aircraft, prompting the FAA to halt departures, The Guardian reported. The FAA later moved the Philadelphia TRACON to a new fiber-optic link with New York on two separate paths as part of measures to improve reliability.

The FAA handles more than 44,000 flights a day and about 3 million passengers, the GAO noted. The GAO also pointed to jamming and spoofing abroad, noting that Estonia and Finland have accused Russia of interfering with satellite navigation in their airspace, which Moscow denies. One incident last September involved a Spanish military jet carrying the country’s defense minister.