Incident Overview
While landing at approximately 20 feet above ground level, the flight crew heard a propeller transition into beta mode. This event caused the aircraft to yaw to the right. The pilot lost control of the aircraft, which subsequently collided with a snow bank. The impact resulted in the separation of the wings from the fuselage. Investigators were unable to determine why the propeller entered beta mode because of damage sustained during the collision.
Probable Cause Findings
The official investigation identified three occurrences and related findings:
Occurrence #1: Airframe/Component/System Failure or Malfunction
- Phase of operation: Landing – flare/touchdown
- Findings:
1. Propeller system/accessories, pitch change mechanism – undetermined 2. Propeller system/accessories, reversing system – undetermined 3. Propeller system/accessories, prop control unit – undetermined
Occurrence #2: Loss of Control – On Ground/Water
- Phase of operation: Landing – flare/touchdown
- Findings:
4. Directional control – not maintained – pilot in command 5. Remedial action – not used – pilot in command 6. Ground loop/swerve – uncontrolled – pilot in command
Occurrence #3: In-Flight Collision with Terrain/Water
- Phase of operation: Landing – roll
- Findings:
7. Terrain condition – snowbank