What happened
On the afternoon of February 7, 2021, a Cessna 150 was conducting a training flight at the Lahti-Vesivehmaa aerodrome. The flight involved a student pilot and a flight instructor performing a series of landings on runway 25. During the third landing, the student pilot was operating the aircraft alone.
The weather conditions were cloudy, and the runway was covered in snow, which obscured the clearly defined runway edges. During the landing roll, the aircraft was tracking to the right to compensate for a crosswind. As the instructor retracted the flaps, the student pilot waited for instructions to increase power and turn off the carburetor heat for the subsequent takeoff. During this period, the pilot failed to notice that the aircraft was drifting toward a snowbank at the edge of the runway.
The right main gear struck soft snow, causing the aircraft to veer sharply to the right. The aircraft left the runway, struck a snowbank, and subsequently capsized, landing upside down on its nose and left wingtip. The student and instructor remained suspended by their safety belts until the student manually disconnected the master switch. Both occupants were able to exit the aircraft through their respective doors without injury.
The investigation
The investigation examined the sequence of events, the environmental conditions, and the operational procedures of the flight school. Investigators reviewed the technical state of the aircraft, OH-DBS, and analyzed the runway conditions at the time of the accident. The investigation also looked into the training organization's safety management and the effectiveness of risk assessments regarding winter operations at uncontrolled aerodromes.
Findings
- The primary cause of the accident was the failure to maintain the aircraft on the runway centerline during the landing roll.
- The student pilot did not observe the aircraft drifting toward the edge of the runway.
- The instructor's attention was focused on the flap position indicator rather than the runway environment.
- The presence of snow on the runway made it difficult to distinguish the runway edges.
- The flight school's risk assessment did not sufficiently account for the specific challenges of operating at an uncontrolled aerodrome during winter conditions, such as obscured runway markings and snow accumulation.