What happened
On the evening of March 27, 2009, at 17:36, a PIK-16c Vasama glider was performing a landing on a cleared ice strip on Lake Jämijärvi. During the final stages of the approach, the pilot decided to execute a non-standard landing pattern. This maneuver involved flying at a higher airspeed than usual and performing a much wider and more distant base turn.
As the aircraft turned onto the final approach, it flew at an extremely low altitude over the Syväsalmi Sound, passing below the treetops. To follow the contours of the sound, the pilot had to turn right. Due to the prevailing lighting conditions, the pilot failed to detect a 20 kV transmission line spanning the water. The aircraft struck the lines, causing damage to the electrical infrastructure, and subsequently crashed into the lake ice, where the aircraft was destroyed. The pilot died instantly.
The investigation
The investigation examined the pilot's flight profile, the environmental conditions, and the visibility of the obstacle. Investigators found that the pilot was a meticulous and careful flyer who did not typically engage in risky behavior. However, the decision to fly the unconventional approach was made spontaneously and without adequate preparation.
Several factors contributed to the error, including the pilot's focus being consumed by the atypical maneuver, a likely desire to return home quickly, and the awareness that the ice flying season was ending. Additionally, the positioning of the landing strip's northern end was closer to the Syväsalmi Sound than in previous years, which influenced the flight path. The investigation also noted that the transmission line was not marked with warning spheres and was difficult to see in the low light.
Findings
- The primary cause of the accident was the pilot's decision to fly a non-standard landing pattern.
- This decision resulted in a flight path so low that a collision with the power lines became unavoidable.
- The prevailing lighting conditions made it impossible to detect the lines in time.
- The pilot's attention was diverted by the complexity of the non-standard maneuver, leading to the oversight of the electrical hazard.
- The placement of the seasonal ice runway closer to the sound than in previous years contributed to the dangerous approach geometry.