Greek authorities investigating the recent blackout in the Athens Flight Information Region (FIR) say the incident was not caused by sabotage, cyber interference, or foreign involvement, but by a widespread failure in a telecommunications system used for air traffic communications.
The head of Greece’s National Cybersecurity Authority, Michalis Bletsas, said investigators are confident about what happened during the outage but are still examining how the failure occurred and how similar incidents can be prevented in the future. He emphasized that no external interference was detected.
According to Bletsas, who is also a researcher at the MIT Media Lab, the disruption stemmed from the remote operation of transmitters used for voice communication between air traffic control and aircraft. A large number of transmitters remained active simultaneously, with some producing no sound and others emitting buzzing or broadband noise.
This malfunction effectively occupied critical radio frequencies, creating what Bletsas described as a “denial of service” situation that prevented normal communications. Because the frequency spectrum was already taken over by the faulty transmissions, backup systems were unable to operate. “When many transmitters continuously broadcast on the same frequency, that frequency becomes unusable,” he said, noting that no alternative spectrum was available.
Authorities also addressed concerns about flight safety, firmly rejecting claims that aircraft were flying without guidance. Bletsas said the incident caused significant inconvenience to passengers, including flight cancellations and delays, but did not pose any risk to aviation safety.
He strongly dismissed speculation about jamming or sabotage, stating that the system’s own transmitters were responsible for occupying the spectrum. While investigators are still gathering data, he said the likelihood of malicious action has diminished as the inquiry progresses.
A special investigative committee was formed instead of using Greece’s standard aviation accident body, a decision officials said was made to ensure faster and more comprehensive coordination among multiple agencies involved. Bletsas added that a human factor, possibly a technical error, remains a plausible explanation.
He also noted that such failures are not unique to Greece, pointing out that similar system breakdowns have led to shutdowns of even larger airspace regions internationally. As aviation systems grow more complex, he said, failures are inevitable, and the key challenge is ensuring resilience so disruptions have limited impact.
