A Financial Times correspondent who was on board wrote that the plane circled in the air for an hour until the pilot landed with the help of paper maps. The Bulgarian government said in a statement that the GPS signal was lost as the plane approached the city of Plovdiv.
The incident occurred during Leyen's four-day trip to EU member states bordering Russia, Belarus, or the Black Sea.
The report of the disruption was also confirmed on Monday (September 1) by EU spokeswoman Arianna Podestová, who, citing Bulgarian authorities, added that there was suspicion of Russian interference.
With this motive, the report was picked up by leading international media outlets.
The EU did not disclose any further details, but the spokesperson stated that the incident would reinforce “the Union's unwavering determination to strengthen its defense capabilities and its support for Ukraine” against the Russian invasion that has been ongoing for three and a half years.
We are all on the eastern flank, Rutte explained
EU Defense Commissioner Andrius Kubilius said the Union would increase the number of its low-orbit satellites to improve the detection of interference. Italy began to consider keeping the routes of government flights secret.
The alleged incident did not go unnoticed by the North Atlantic Alliance either.
“The entire continent is under direct threat from Russia,” NATO Secretary General Mark Rutte said during a press conference in Luxembourg on Tuesday alongside the country's prime minister and defense minister. “We are all now on the eastern flank—whether you live in London or Tallinn,” he added.
He noted that the alliance is working “day and night” to prevent GPS signal interference and ensure that “something like this does not happen again.”
The flight tracking service
Flightradar24, a service for tracking flights in real time, questioned the European Union's version. In a post on social network X, the service stated that the aircraft's transponder reported good GPS signal quality throughout the flight, from takeoff to landing.
According to online data, the planned flight time was 1 hour and 48 minutes, but the flight actually lasted 1 hour and 57 minutes, only nine minutes longer.
SkAI Data Services, a technology startup specializing in aviation data based in Switzerland, stated on LinkedIn that “regional disruptions at higher altitudes were detected in the region,” but the flight data does not indicate that von der Leyen's aircraft lost its GPS signal.
We are seeing media reports of GPS interference affecting the plane carrying Ursula von der Leyen to Plovdiv, Bulgaria. Some reports claim that the aircraft was in a holding pattern for 1 hour.
— Flightradar24 (@flightradar24) September 1, 2025
This is what we can deduce from our data.
* The flight was scheduled to take 1 hour… pic.twitter.com/qiSNfCTJtZ
Furthermore, Russia denied responsibility for the navigation system failure. “Your information is incorrect,” Kremlin spokesman Dmitry Peskov said on Monday.
The European Commission calms the situation
On Tuesday, Von der Leyen's chief spokeswoman Paula Pinho was more cautious in her comments. Without going into detail, she confirmed to journalists that there had been GPS interference and that the plane had fortunately landed safely. She reiterated that the Bulgarian air traffic control authorities were the first to confirm the incident.
Pinho did not comment on questions about the pilots' use of paper maps. She was also unable to provide any details about the flight time, only that it had taken “significantly longer” than planned.
Paper maps are not necessary
The original FT report also omitted other details.
Róbert Breda from the Department of Aeronautical Engineering and Marek Češkovič from the Department of Avionics at TUKE told Štandard that modern commercial aircraft are equipped with at least two receivers for satellite navigation signals.
This means that they also receive signals from the European Galileo system, BeiDou or GLONASS, depending on the aircraft's on-board equipment. [The GLONASS navigation system can be used by all users, including those from abroad, editor's note.]
"The articles I followed in the press did not mention these systems at all and did not list them as basic navigation systems for short-range navigation in the event of a loss of GPS signals.
An aircraft equipped with these systems can navigate safely even if the GPS signal is lost or disrupted, but this places higher demands on the pilot's skills, especially during the landing phase," explains Breda.
Češkovič adds that modern aircraft have other options besides satellite system signals. "For example, an inertial system based on the movement of the aircraft, but regularly corrected with the help of GPS. In addition, systems such as VOR and DME help to determine the direction and distance to a fixed station on the ground, often located at the airport where the aircraft is to land. To use these older systems, pilots need aeronautical charts, which can be in paper or digital form. In addition, they can also navigate visually from the cockpit using the terrain and known landmarks. Furthermore, an air traffic controller on the ground can help them by tracking them on radar and guiding them to the correct route or landing with the help of radio commands," explains the expert.
Disruptions are common in conflict areas
On Tuesday, Bulgarian Prime Minister Rosen Željazkov toned down his claims of direct Russian interference, describing the incident as a routine disruption resulting from the far-reaching effects of the war in Ukraine.
“There is no need to investigate the situation, as such interference does not pose a hybrid or cyber threat,” Politico quoted the Bulgarian prime minister as saying. He described such radio-electronic interference as common since the beginning of the conflict in Ukraine.
Expert Češkovič explains that disruptions occur near military conflicts because combat equipment and smart munitions use satellite navigation signals for target acquisition.
They are Drama queens. GPS spoofing (and jamming) is quite normal in the area. There are normal procedures to deal with it. Almost any pilot nowadays has experienced gps jamming and spoofing. Its a pain in the ass but nor complicated to deal with. There are even maps in real time… pic.twitter.com/1ix1EQstRj
— Carlos Perez Ferrer (@carlospapafox) September 1, 2025
Signal interference occurred, Leyen's office reiterates
Commission spokeswoman Arianna Podestová emphasized on Thursday that the Commission had never claimed that the reported GPS signal interference was linked to targeted activities, nor had it commented on how long the aircraft had circled over Plovdiv before landing. However, citing the Bulgarian authorities, she insisted that “a GPS signal disturbance occurred.”
Nevertheless, she noted that Brussels did not intend to investigate this incident and that it was up to the Bulgarian authorities to decide how to proceed in this matter.
Bulgaria claims the opposite
On Thursday, the relevant authorities also commented on the situation. However, their statements contradict those from Brussels.
Bulgarian Prime Minister Rosen Željazkov explained the incident to members of parliament.
He stated that the three regulatory authorities responsible for the radio frequency spectrum—the Communications Regulation Commission, the State Agency for National Security, and the ATSA Agency—had not detected any GPS signal interference in the area of Plovdiv Airport that would have affected flight navigation or the landing system.
No other aircraft had reported such interference at that time and in that area. Communications between the captain, the crew, and air traffic control showed no signs of concern or distress.
Throughout the flight, Leyen's aircraft transponder transmitted continuously and the GPS signal was of good quality. The politician emphasized twice that the delay was only five minutes, which is within the permissible limit.
The Bulgarian Prime Minister stated that flight events related to GPS signal interference do not necessarily have to be investigated under current regulations. The final decision on the need for an investigation rests with the National Authority for the Investigation of Accidents in Air, Water, and Rail Transport.
“The reason Bulgaria decided not to investigate the incident may be political or pragmatic in nature—there was no official report of the situation as a flight accident,” concludes Češkovič.