US airports ground stop after radio issue as security concerns raised

Flights into three major airports in the US Northeast were halted by a radio equipment problem on Monday, just as a government watchdog released a report warning that the systems guiding aircraft are open to interference and deception.

The Federal Aviation Administration ordered a ground stop at about 10am Monday for Newark Liberty international, Philadelphia international and Teterboro airports. Radio frequencies at the Philadelphia terminal radar approach control were affected until the early afternoon. Arrivals and departures at Newark were delayed, and the agency has not said what caused the outage.

The disruption coincided with a government accountability office report finding that the FAA has yet to finish risk assessments or update security documentation covering threats from spoofing, jamming and other attacks on the radio spectrum. The watchdog also noted the FAA lacks a real-time system to detect all such threats, meaning it can generally 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. This could cause delays, disrupt airspace or create safety risks. Two systems used to send text messages to aircraft predate modern cybersecurity standards and lack encryption.

Ron Wyden, the US senator for Oregon, called the vulnerabilities a "major threat to US national security, to our economy and the safety of the flying public." Wyden said the report reveals air traffic technology is "incredibly insecure" and can be intercepted, impersonated and jammed by hackers and foreign governments.

The GAO made nine recommendations, including a formal risk assessment of seven of eight reviewed systems, continuous monitoring for interference, and formal guidance on information sharing. The department of transportation agreed with all nine recommendations. The GAO noted the FAA handles more than 44,000 flights a day and about 3 million passengers.

Monday's disruption is the latest in a run 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 agency has since moved the Philadelphia Tracon to a new fiber-optic link with New York to improve reliability.

Wyden urged the FAA to issue new standards immediately to protect airline communications. The GAO highlighted similar issues abroad, with Estonia and Finland accusing Russia of interfering with satellite navigation in their airspace, a claim Moscow denies. A separate incident last September involved a Spanish military jet.