What happened
The pilot was conducting an agricultural application flight, specifically spraying a corn field, when the engine suddenly failed. The loss of power necessitated an immediate straight-ahead forced landing attempt. During the subsequent landing roll, the aircraft's wheels became bogged down in the soft earth of the field. This resistance caused the plane to overturn.
The investigation
Following the accident, the pilot conducted a post-impact examination of the engine to determine the cause of the failure. The inspection revealed that the dowel pin on the magneto impulse coupler had been sheared off by the main crankshaft drive gear. This mechanical separation prevented the ignition system from functioning correctly, leading to the in-flight power loss.
Findings
The primary factor in this accident was the sheared dowel pin on the magneto impulse coupler. The failure of this component resulted in engine failure during a critical phase of flight. The subsequent forced landing in an agricultural field contributed to the severity of the damage, as the soft ground conditions caused the aircraft to overturn upon touchdown.