The blackout that froze flights in Greece - How the Greek FIR was paralyzed yesterday, what happened

Airports have grounded takeoffs and suspended landings, while flights crossing the country at altitudes above 28,500 feet have ground to a halt, and Greece has been facing an unprecedented air traffic blackout. The serious problem, which began yesterday morning and lasted for at least 9 hours, led to the cancellation of 53 arrivals and 54 departures from airports across the country.

It all started when a problem occurred simultaneously on multiple frequencies of the Hellenic Civil Aviation Authority (HCAA), an incident that officials initially described as “massive interference” and “unprecedented phenomenon.”

The CAA announced late yesterday afternoon that the problem has now been resolved, noting that it is working closely with OTE to fully document the incident and take preventive measures. At the same time, CAA engineers are conducting checks at all relay stations, while a check flight was carried out yesterday with an CAA aircraft, with the assistance of EETT. OTE, for its part, clarified that the circuits it provides to the CAA are fully operational and are not related to other systems of the service.

The effects were immediate and visible throughout the country. Aegean Airlines, in an official announcement, informed that all its flights to and from Greek airports were delayed or forced to be suspended, while for those that had already started routes within the Greek FIR, the company emphasized that international safety protocols were strictly adhered to. “The safety of our passengers and staff is an absolute priority,” the announcement said.

Retired Lieutenant General Athanasios Papanikolaou, speaking to iefimerida, describes the incident as unprecedented in intensity and duration. “When the Athens and Macedonia Control Centers are simultaneously affected and a total suspension of takeoffs and landings is activated, the issue is not simple,” he says, explaining that the possible scenarios “include malicious action, technical failure or human error.” At the same time, he does not rule out the participation of state entities or companies that are pushing for the sale of new systems, demonstrating the weaknesses of the existing infrastructure. “We cannot rule out anything, but it is clear that something did not work as it should.”

The incident also highlighted another chronic weakness, as Mr. Papanikolaou mentions, which is the absence of the digital CPDLC (Controller-Pilot Data Link Communications) system. “It is a digital communication channel between pilot and controller, which allows sending text messages instead of voice communication. In most European countries, CPDLC has been installed, ensuring contact with aircraft even when voice frequencies are damaged or interfered with. In Greece, however, it does not exist. Here in Greece we do not have it. Why we do not have it, I do not know,” says Mr. Papanikolaou, noting that the absence of the system makes the Greek sky particularly vulnerable to crises.

According to people who know how the systems work, a simple technical failure is not enough to explain the full picture. Flight control systems are designed to withstand even when one part of them has a problem. The fact that critical functions “fell down” at the same time points to either a failure of the backups or a common point of failure, which is considered particularly serious for infrastructures of national importance. Greece manages one of the most complex airspaces in Europe, with a huge volume of flights, especially in the summer months, but without always corresponding infrastructure and modern systems.

The scenario of a cyberattack cannot be ruled out, although some experts emphasize that air traffic control systems are not fully exposed to the internet. The incident revealed in the most dramatic way how fragile Greek airspace is and how much there is a need to modernize and strengthen the systems.

According to Civil Aviation unionists, the blackout was not a simple technical failure, but the result of decades of underinvestment, old equipment and shortages in reserves. The country's skies were closed for several hours, reminding everyone that the safety, reliability and international image of the Greek FIR are not a given and require immediate attention and action. In its latest announcement, the Hellenic Civil Aviation Authority, issued late yesterday afternoon, stated that during the incident, flight safety was fully ensured, in accordance with international standards. At the same time, investigations into what caused the problem continue.