Safety Investigators Issue Interim Report onEura Aviation Accident: Collision Helicopters Were not in Formation

Two helicopters en route from Tallinn, Estonia, to Piikajärvi, Finland, were involved in a mid-air collision at 1234 local time on Saturday May 17, 2025. The accident occurred to the north of Eura aerodrome approximately 200 meters above ground level. The helicopters were destroyed and all five occupants sustained fatal injuries. Fuel and oil leaked from the wreckages and caused soil contamination.

“Detailed analysis of flight track data will still be needed. We have radar data, but we must dig deeper into it and correlate the data with other information. The helicopters flew in close proximity, and their relative position changed repeatedly with each helicopter taking turns in the lead and trail position, while separation between the helicopters varied from a few hundred meters to considerably less,” explains investigator-in-charge Janne Kotiranta.

“Just before the collision, they were proceeding northwest in the direction of Eura aerodrome. Right before the impact, the red helicopter, registration ES-ETR, was positioned to the left of the black helicopter, OE-XOS. When overhead the aerodrome, the red helicopter made a right-hand turn to north, while the black helicopter continued to track northwest, and the helicopters collided. The cause is as yet undetermined.”

“I’d like to add that although media used the term ‘formation flying’ to describe the way the helicopters were grouped, they were, as a matter of fact, not flying in a formation. In a formation, flight members use predetermined radio calls on a common frequency to transmit messages related to formation management, such as aircraft positioning and separation between individual aircraft. There is also a designated formation leader who will retain this role throughout the entire flight. Roles, separation criteria and other such things are agreed before the flight and they will be adhered to,” Kotiranta states.

The tail boom of each helicopter separated on impact, and the main rotor systems disintegrated. Debris was scattered over a large area in forested terrain north of the aerodrome. Post-crash fire consumed the fuselage of the red helicopter.

The SIAF is continuing further examination of the wreckages as well as collision modelling and detailed track analysis. It also continues the review of airworthiness aspects and pilot-related factors, including the pilots’ licenses and experience.

“While the helicopters were not fitted cockpit voice recorders, a video camera captured events in both cockpits, and therefore we cannot say that there were no audio recording devices, because there were these cameras. The camera on board the red helicopter was destroyed by fire. The device on the other helicopter malfunctioned, and we have so far been unable to extract data from that camera, even with assistance from our foreign counterparts”, Kotiranta explains.

“Neither were the helicopters equipped with flight data recorders, or ‘black boxes.’ However, there were navigation and other automated systems, including a so-called autopilot, and investigation of their partially destroyed memory circuits is ongoing. We have discussed the matter with our French colleagues, who have a lab where memory circuit data can possibly be retrieved, but of course we do not know whether extracted data will yield additional information for investigation purposes; in other words, the value of data cannot be determined at this point,” Kotiranta concludes.

The duration of the safety investigation is approximately 9 to 12 months.

The National Bureau of Investigation (NBI) continues its criminal investigation into the accident and the cause of death. The NBI will provide further information as the investigation progresses.

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Further information:

Investigator-in-Charge Janne Kotiranta: tel. +358 2951 50703