What happened
While operating the aircraft in cruise flight, the pilot noticed a significant reduction in engine power. He immediately initiated emergency procedures to address the mechanical issue; however, the engine continued to lose power despite these efforts. Unable to maintain altitude or airspeed, the pilot was forced to execute an emergency landing. During this maneuver, the airplane collided with trees.
The investigation
Following the accident, a detailed post-accident examination of the engine was conducted. The inspection revealed that the engine crankshaft had separated into three distinct pieces. An inspector noted that the failed crankshaft showed clear evidence of a fatigue fracture, indicating a structural failure rather than an operational error.
Findings
The primary factor in this accident was the mechanical failure of the engine components. Specifically, the fatigue fracture of the crankshaft led to the complete loss of engine power. The pilot's decision to perform a forced landing was a direct response to this sudden mechanical failure.