A massive radio blackout that paralyzed Greek airspace on Jan. 4 was caused by obsolete technology rather than a cyberattack, a government probe has concluded, exposing deep structural flaws in the country’s aviation infrastructure.
An expert committee appointed by the Infrastructure and Transport Ministry found “no indications of cyberattack or external malicious interference” in the incident, which severed communications between air traffic controllers and pilots for hours.
Instead, the report blamed the outage on “digital noise” triggered by a loss of synchronization across the network.
The technical glitch caused a “critical number” of transmitters to broadcast continuously and unintentionally, effectively jamming the frequencies used by the Athens and Macedonia regional control centers.
The root cause, investigators found, is the Civil Aviation Authority’s reliance on outdated Synchronous Digital Hierarchy (SDH) technology.
The report noted this legacy system is “no longer supported by the manufacturer” and cannot offer “effective guarantees for its operation.”
“No issue of aviation security… was noted,” the ministry stated, emphasizing that aircraft already in the air were never exposed to direct threats.
The incident was officially assessed as low-risk, though it forced a ground stop that stranded thousands of passengers.
To prevent a recurrence, the committee recommended an urgent overhaul of the country's aviation comms.
Key proposals include a rapid transition to Voice over IP (VoIP) technology, the installation of a new radio communication system, and the procurement of nearly 500 new transceivers.
The report also called for a unified immediate response mechanism between aviation authorities and telecom providers to handle future disruptions.
The system was eventually restored shortly before 5 p.m. on the day of the blackout after technicians performed a hard reset of the network.