Pilots Were Unable to Contact Denver Air Traffic Controllers for Several Minutes

On May 12, pilots flying into Denver International Airport briefly experienced every aviator’s least favorite scenario: radio silence from air traffic control. According to the Federal Aviation Administration, the 90-second communications failure was caused by “overlapping outages to radio transmitters and circuits” at the Denver ARTCC in Longmont, Colorado.

The FAA says that, despite the glitch, all aircraft remained safely separated. Controllers quickly pivoted to emergency communication channels, and operations continued without a reported incident. Local reports initially suggested some pilots were out of contact for up to six minutes. That version of events was firmly disputed by the FAA, which maintains the disruption lasted just a minute and a half.

The affected Air Route Traffic Control Center (ARTCC) facility is one of 22 en route centers in the country, responsible for managing aircraft flying at higher altitudes across roughly 285,000 square miles of airspace. This includes not only Colorado but parts of Wyoming, Utah, Kansas, Nebraska, New Mexico, South Dakota, and Arizona.

According to testimony from FAA officials, both the main and backup radio frequencies failed, leaving controllers to resort to an emergency “guard” frequency typically reserved for distress transmissions. One pilot reportedly used it to relay instructions to other aircraft until communication was re-established.

Though no passengers were ever in danger, and no aircraft came too close to another, the outage has raised eyebrows, especially in light of recent scrutiny over FAA oversight and infrastructure resilience. The incident follows multiple radar and communications failures at the Philadelphia center that impacted flights to and from Newark just weeks earlier.

The FAA has since replaced the faulty transmitters and repaired the circuits. Still, given Denver’s average of 1,900 daily aircraft movements, even a short lapse in communication is enough to raise serious safety concerns… and even more serious questions about redundancy in air traffic systems.

FMI: www.faa.gov