Incident Overview
A pilot experienced a partial power failure while operating the aircraft. The loss of engine power necessitated a forced landing to an open field. The field surface was wet and soft, which contributed to the aircraft's behavior during the landing roll.
Forced Landing and Nose-Over
During the landing roll, the nose wheel failed aft—collapsed or rotated backward—causing the airplane to nosed over. The soft and wet field conditions likely exacerbated the nose wheel's failure and the subsequent overturn.
Postimpact Examination
After the accident, an examination of the engine revealed the cause of the partial power failure. The castellated nut that secured the throttle cable in place had backed off and separated from the aircraft. This displacement allowed the throttle cable to move, which in turn permitted the engine to transition to the idle power setting, resulting in the loss of power.
Mechanical Findings
The separation of the castellated nut from its intended position was the direct mechanical anomaly identified. With the throttle cable no longer properly retained, the engine's throttle could not be maintained at the desired setting, leading to the partial power condition that prompted the forced landing.