Sabotage Ruled Out in Greek ATC Outage Investigation

The Hellenic Civil Aviation Authority (HCAA) has no initial reason to believe last Sunday’s air traffic control service outage was caused by foul play, the regulator has revealed, as an investigation “to clarify the exact cause of the problem” has been initiated.

Just before 9 a.m. on the morning of January 4, the primary and backup communications systems serving Greece’s Athens Area Control Centre failed, affecting almost the entirety of the Athens Flight Information Region (FIR). The HCAA described the interruption as “a form of continuous ‘noise’ interference in the listening of [multiple] frequencies, originating from unintentional signal emissions of the service’s transmitters.” This was accompanied by malfunctions in the telephone lines and data circuits.

Following what the Air Traffic Controllers European Unions Coordination (ATCEUC) called an “unprecedented failure,” a NOTAM was issued to suspend all non-airborne flights within the Athens FIR. “For two critical hours, Greek colleagues worked tirelessly to safely clear the remaining aircraft from the airspace,” explained ATCEUC. From midday, flight operations began to be gradually restored, before the Hellenic Aviation Service Provider (HASP) confirmed full operational capacity had been restored at around 5 p.m. local time.

Ongoing Investigation and Modernization

On the day of the event, Greek government spokesperson Pavlos Marinakis stated that “there is not the slightest indication that we are dealing with a cyberattack.” This was supported by the initial findings of the HCAA, which explained that initial inspections of relay station electronics were completed “without any relevant evidence directly linked to the incident emerging.”

“The investigation so far appears to identify the problem in telecommunications infrastructure and did not reveal any evidence of a cyberattack,” clarified the HCAA. A special committee, which first met at the Athens and Macedonia area control centers on January 6, will now work to “clarify the exact cause on the problem.”

However, the Chair of the Association of Greek Air Traffic Controllers cautioned that “this incident once again exposes the critical weaknesses of outdated and underfunded air traffic management infrastructure.” Although “safety was maintained due to human expertise…this cannot continue to compensate for systemic deficiencies,” he stressed. ATCEUC added that “critically low revenue levels of HASP…are fundamentally incompatible with the safety and performance requirements…and remain far below the European average.”

However, the government highlighted that an ongoing modernization program of Greek ATC systems is already underway, with HASP advancing the upgrade of voice control and remote control systems at the Athens area control center. This “comprehensive action plan,” intended to improve reliability and resilience of services, is set to be completed by 2028.