Incident Overview
A student pilot was conducting a solo cross-country flight when a partial loss of engine power occurred. The pilot applied carburetor heat, but the engine continued to run rough. An emergency landing was performed on upward sloping terrain. During the landing roll, the nose gear encountered a hole in the dirt, causing the aircraft to nose over.
Post-Accident Examination
An examination of the engine revealed that the retaining nut on the #3 exhaust valve had backed off. As a result, the valve would not operate as the crankshaft rotated. Maintenance had been performed on the previous day, during which the #3 valves had been adjusted.
Sequence of Events
The student pilot was on a solo cross-country flight when the engine power partially failed. Despite applying carburetor heat, the engine continued to run roughly, prompting the pilot to initiate an emergency landing. The touchdown occurred on terrain with an upward slope. During the rollout, the nose gear dropped into a hole in the dirt, and the aircraft nosed over. No injuries were reported in the source.
Findings
The investigation identified that the #3 exhaust valve retaining nut had loosened, leading to valve malfunction. The valve adjustment performed the previous day was noted as a relevant maintenance event. No other contributing factors were mentioned in the source.