What happened
The pilot of the aircraft experienced an engine running rough during flight and decided to perform an off-field precautionary landing. In an attempt to rectify the engine issue, the pilot checked the magnetos and carburetor heat and pumped the throttle; however, these actions did not resolve the roughness.
The pilot selected a hayfield for the landing. During the landing sequence, the pilot applied braking to account for the short field and various obstructions, which caused the aircraft to nose over.
The investigation
Following the accident, FAA inspectors examined the engine and the airplane after they were transported from the accident scene. The inspection revealed no evidence of a mechanical problem that could have been responsible for the reported rough-running engine.