A serious technical problem with the radio communications of the Area Control Centers caused significant disruption from the early hours of Sunday, January 4, 2026, resulting in flights being grounded at all Greek airports and affecting the overall operation of the Athens FIR. The problem had a direct impact on both Athens International Airport «Eleftherios Venizelos» and regional airports across the country, causing cancellations, flight diversions, and long delays.
According to the Civil Aviation Authority, the gradual restoration of the Air Traffic Control System began early in the afternoon. A limited number of takeoffs and landings are now being handled, with strict restrictions for safety reasons. At Athens airport in particular, some departures returned to parking positions, flights were diverted to other airports, and dozens of flights were delayed or canceled.
In a recent announcement, the HCAA stated that up to 35 departures and arrivals are currently being served nationwide, while overflying traffic is being partially carried out in restricted areas, in coordination with EUROCONTROL. At the same time, an updated NOTAM notice has been issued.
According to investigations so far, the problem is attributed to damage to the Hellenic Civil Aviation Authority's antenna in Gerania Mountains. The National Cyber Security Authority and the EYP conducted checks, ruling out the possibility of a cyberattack or sabotage. The OTE Group, for its part, clarified that the circuits it provides to the HCAA are operating normally and are not related to the malfunction.
The situation remains under close monitoring, with the competent authorities assuring that flight safety is a priority and that further updates will be provided as the system is fully restored. Passengers are advised to contact their airlines for up-to-date information on their itineraries.
