Nearly 123,000 flights were affected by interference traced to Russian territory in the first four months of 2025, according to a joint submission to the International Civil Aviation Organization (ICAO) by Sweden and five neighbouring states. The authorities describe the trend as a significant and growing threat to international flight safety.

Sweden’s Transport Agency (Transportstyrelsen) has reported a marked rise, in recent months, in alerts concerning interference with satellite-based navigation used by civil aviation. The new international report, compiled with counterparts around the Baltic Sea, sets out the scope in detail and attributes the disruption to deliberate electronic measures emanating from multiple locations in Russia.

Between January and April 2025, a total of 122,607 flights operated by 365 airlines experienced interference with Global Navigation Satellite Systems (GNSS), which include GPS and other constellations. In April alone, an average of 27.4% of flights within the affected airspace encountered disruption; in some areas the proportion exceeded 42%. The effects recorded range from false position indications to cascading system faults that can persist for the remainder of a flight, even after leaving the most affected zones.

“We regard the situation as serious because we continue to see an increase in interference rather than any sign of it abating,” said Andreas Holmgren, a unit head at Transportstyrelsen. He added that it is troubling to see a deliberate effort to degrade a global system used across many sectors, not just aviation.

The participating authorities report that they have geolocated sources of interference to sites in Kaliningrad, St Petersburg, Smolensk and Rostov. The disruptions comprise both jamming — blocking or overwhelming legitimate satellite signals — and spoofing, in which false GNSS signals deceive onboard receivers and avionics. While modern airliners carry multiple, layered navigation and landing aids, the authorities warn that sustained interference can complicate flight operations and increase workload for crews and air traffic control.

Air navigation service providers and European agencies have issued special notices to pilots and operators, advising carriers to strengthen operational readiness, review procedures for GNSS-denied environments, and ensure that flight crews are briefed on recognition and management of both jamming and spoofing events. According to the submission, the interference has affected airspace over Poland, the Baltic states, Finland and Sweden, with some aircraft continuing to register degraded performance after transiting the most affected areas.

The Swedish government is monitoring the situation. Defence Minister Pål Jonson said Stockholm is prepared for continued attempts at disruption and pressure, stating that authorities have the readiness to respond to these types of threats. The statement follows the pattern observed in recent months, during which operational advisories have been updated and cross-border technical monitoring intensified.

GNSS provides position, navigation and timing data foundational to modern aviation, including en-route navigation, performance-based approaches and timing for communications and surveillance systems. While airliners retain conventional aids and inertial systems, sustained interference can trigger reversionary modes, force procedure changes and, in some cases, necessitate diversions or delays. The report’s authors state that the scale recorded from January to April indicates a systemic challenge rather than isolated incidents.

The authorities’ geolocation work relied on field measurements and comparative analysis across multiple national monitoring networks. By correlating aircraft reports with ground-based detection of anomalous radiofrequency activity, they identified repeat emitters consistent with high-power jammers and spoofers. The submission does not disclose technical parameters or the precise sites of the emitters, but it states that the sources were persistent and that their effects were observed across borders.

Regulators and operators have, in response, emphasised crew training, redundancy management and the use of alternative navigation methods when GNSS is unreliable. Airlines have also been advised to review dispatch planning, ensuring availability of routes and alternates that mitigate exposure to the most affected sectors. The report notes that interference can “follow” an aircraft, in that equipment may remain in a faulted state until reset or until the aircraft reaches its destination, underscoring the need for clear cockpit procedures.

The submission asks ICAO to consider the safety implications at a global level and to support coordinated mitigation, data-sharing and investigation. It also highlights the wider societal reliance on satellite-based services, calling attention to the potential for spill-over effects in other sectors that depend on precise timing and positioning.

The authors conclude that the quantity of affected flights, the breadth of the airspace involved, and the upward trajectory observed through April warrant continued international attention. They state that while the aviation system is designed with layers of resilience, deliberate interference at this scale imposes risks that require sustained monitoring, operational adaptations and diplomatic engagement.

First published on eutoday.net.