A radio failure caused a collapse in air traffic communications in Greece on Sunday Jan. 4, grounding flights, diverting international services, and leaving passengers stranded, as authorities scrambled to restore order and launch an official investigation.
Radio failure caused disruptions in several countries
The disruption began just before 9 a.m. local time on Jan. 4, when multiple radio frequencies used by air traffic controllers across the Athens and Macedonia Flight Information Regions failed or became unreliable, the Hellenic Civil Aviation Authority said. Controllers could not maintain regular voice contact with aircraft, prompting a safety shutdown of departures and arrivals at Greek airports.
To manage the situation, the authority issued a NOTAM, declaring a “zero rate” for flight operations in Greek airspace. The directive effectively halted all new takeoffs and landings during the busiest post-holiday travel weekend of the year.
With communication channels compromised, airport screens across the country were filled with delayed and cancelled flights. Athens International Airport, Thessaloniki Airport and multiple regional airports were affected, as staff and air traffic controllers worked to keep planes already airborne safe and to coordinate limited overflights.
The outage had broad operational impacts. Aegean Airlines reported 48 cancellations, representing about 12 per cent of its scheduled domestic and international services for the day. Flight tracking data showed that Greek skies were nearly empty during the shutdown, a key international corridor for flights between Europe, the Middle East and Africa.
Inbound international flights were diverted to alternate airports in Italy, Croatia, Hungary, Albania and Cyprus, while some long-haul services from the Gulf and other regions returned to their origin airports. Hundreds of other departures were delayed, and average delays at Athens reached more than 100 minutes.
Investigation launched but no evidence of a cyberattack
Operations gradually resumed by the afternoon, once backup frequencies were activated and manual procedures were put in place. Normal air traffic flows were restored by about 5 p.m., and the NOTAM was lifted soon after.
Greek Transport Minister Christos Dimas said there is no evidence of a cyberattack and that flight safety was not compromised at any point. Authorities stressed that onboard systems, radar surveillance and established lost-communication protocols helped aircraft remain safe during the outage.
Officials said the interference affected the central radio systems in a way they have not seen before, and details remain unclear. A judicial inquiry and an internal investigation have been launched to determine the precise cause of the failure, in cooperation with telecommunications specialists and external agencies.
Air traffic controllers’ associations highlighted the age of existing equipment and long-standing calls for upgrades, noting that modern equipment may help prevent similar disruptions in the future.
Was your journey impacted by the radio failure? Let us know in the comments.
