"The same thing happened as the day before. Somewhere halfway along its route, the plane turned back, around 15 minutes before landing. The pilot said that approaching Tartu at night requires an accurate GPS signal, and there was not one because of interference from the eastern neighbors," a passenger, who was on board the flight, told ERR.

On Thursday night, another Finnair plane traveling from Helsinki to Tartu also had to turn around due to GPS interference.

However, the daytime flight from Helsinki to Tartu on Friday had no problems and was able to land in Tartu before later departing for Helsinki on schedule.

"Our pilots are well aware of GPS disturbances, and the aircraft's systems detect GPS disturbances quickly. Our planes use multiple sources to calculate aircraft position, which allows hours of navigation accuracy to be maintained even when GPS is not working. Most airports have standard approach equipment that allows landing without GPS, but Tartu is one of the few airports where approach procedures require a GPS signal, which is why the landing was unsuccessful," Finnair's spokesperson told ERR on Friday.

The spokesperson said that the flight did not divert to Tallinn because, at that time of the night, Finnair didn't have the readiness at Tallinn to arrange accommodation or ground transportation for our customers.

Lotte-Triin Narusk, communications manager of Estonian Air Navigation Services (Lennuliiklusteeninduse AS), told ERR that GPS interference has increased recently and impacts air traffic procedures.

"At Tartu Airport, aircraft can land primarily using GPS-based procedures, with visual approach capabilities also available in good weather. Tallinn is a controlled airspace where EANS provides air traffic control services," Narusk said.

GPS jamming has been taking place since the end of 2022. Russia is thought to be behind it.

However, Aet Härmaorg, marketing communications project manager at Tallinn Airport, which also manages Tartu Airport, told ERR that the Finnair plane's GPS signal was jammed during its flight, not on landing.

In addition to GPS, Tartu Airport also has a one-way instrument landing system  (ILS), Härmaorg said.

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