Bulgaria’s State Agency for National Security (DANS) said it located and neutralized a powerful jammer that was suppressing GPS frequencies across Sofia, including at Sofia Airport (SOF), in a joint operation with the Communications Regulation Commission (CRC) and the Sofia Directorate of the Interior on August 21, 2026.
DANS said in a statement the device was found in a “heavily guarded complex” in the capital’s Dragalevtsi district, and that it had been suppressing the GPS frequencies used by the airport, by aircraft overflying Sofia and by television towers.
The agency provided no details on the type of device, its owner, or its operator, and announced no arrests.
Aircraft switched from satellite to ground-based navigation
Transport and Communications Minister Georgi Peev said on bTV that the interference occurred on August 21, 2026, and was detected immediately. Satellite navigation was compromised, and there was an effect on flight management, he said, but safety was not affected.
Peev said the affected aircraft switched from satellite-based navigation to Bulgaria’s network of conventional terrestrial navaids. Air traffic controllers reported the interference, prompting DANS and the CRC to locate and neutralize its source.
Sofia Airport’s press office told the Bulgarian News Agency (BTA) on August 21, 2026, that operations had not been affected and that flights were running on schedule.
Pilot says disruption lasted at least three days
Aleksandar Bogoyavlenski, a commercial pilot and aviation journalist, told Bulgarian National Radio (BNR) on August 21, 2026, that aircraft departing from and arriving at Sofia had experienced GPS problems for at least three days, and possibly longer, with the signal disappearing almost continuously. No flight safety problems or delays resulted, he said, because aircraft revert to conventional navigation.
Bogoyavlenski described interference persisting over Sofia for several consecutive days as unprecedented. Shorter or intermittent episodes, however, had previously been reported.
The open-source monitoring account GiamMa, using aircraft-derived GPSJam data, reported possible interference anomalies over the capital beginning on August 1, 2024, and again in October 2024.
Oops, again possible GPS/GNSS Jamming interference anomalies in the skies of Sofia, Bulgaria.
— GiamMa-based researchers SDR R&D IoT (@giammaiot2) October 17, 2024
– 13-10-2024 last UpDate gpsjam
– 72h Live GPS Spoofing & Jamming Tracker Map#Bulgaria #Sofia#Jammer #Jamming #Spoofer #Spoofing #GPS #GNSS #ADSB #EW #ElectronicWarfare https://t.co/9hJk71exdV pic.twitter.com/ygO4mIAY2M
GPS World subsequently reported interference in and around Sofia from December 12, 2024, into January 2025. None of those earlier observations have been linked to the jammer found in Dragalevtsi.
GNSS interference has also affected aircraft elsewhere in Bulgaria. A flight carrying European Commission President Ursula von der Leyen encountered GPS jamming while approaching Plovdiv on August 31, 2025. Bulgarian authorities suspected Russian involvement in that incident, but DANS made no attribution concerning the device found in Sofia.
The International Civil Aviation Organization (ICAO) condemned Russia and North Korea over persistent interference in October 2025, and the European Union Aviation Safety Agency (EASA) and Eurocontrol published a joint action plan in March 2026.