What happened
The pilot was conducting cruise flight operations over mountainous terrain while flying a float-equipped airplane. During this phase of flight, the engine experienced a sudden loss of power. In response to the mechanical failure, the pilot initiated an emergency landing procedure on nearby tundra-covered terrain.
During the touchdown and subsequent rollout, the aircraft's floats dug into the soft ground surface. This interaction caused the airplane to turn completely over, resulting in a rollover accident.
The investigation
A postaccident examination of the engine was conducted to determine the root cause of the power loss. The inspection revealed a fatigue failure of the crankshaft, which directly contributed to the sudden stoppage of the engine during flight.