What happened
During a nighttime approach to Vaasa Airport, the aircraft was performing its final turn to align with the runway approach path. During this maneuver, the plane experienced a sudden loss of altitude and collided with trees in a heavily forested region near Koivately, situated approximately 10.5 km from the airport. The impact resulted in a post-crash fire that completely destroyed the aircraft. There were 25 fatalities and no survivors among the occupants.
Findings
Investigations determined that the accident was caused by an incorrectly executed left turn at low altitude, which led to an aerodynamic stall and subsequent spin. The investigation also identified significant human factors contributing to the event. It was concluded that the pilot-in-command was not in a suitable physical or mental state to operate the aircraft due to recent alcohol consumption and a lack of sleep. Furthermore, the crew's readiness for flight was compromised, as the co-pilot should not have been permitted to participate in the mission under such conditions.