What happened
During the third spray run of the day, the pilot reported that the engine lost power unexpectedly. Unable to maintain altitude or return to the airfield, he was forced to execute an emergency landing in an adjacent open field. The terrain consisted of soft mud, which contributed to the severity of the impact. As the aircraft rolled out after touchdown, it nosed over onto its nose.
The investigation
Following the accident, investigators conducted a thorough teardown of the engine to determine the mechanical cause of the power loss. The examination revealed that a camshaft roller, part number 59-99, had failed. This failure caused a valve to stick in the open position, preventing the engine from operating correctly and leading to the subsequent loss of power.
Findings
The primary factor in this accident was the mechanical failure of the camshaft roller. The resulting stuck valve led to engine failure during a critical phase of flight. The soft ground conditions at the landing site exacerbated the damage, causing the aircraft to nose over upon landing.