What happened
Approximately 10 minutes after takeoff, the aircraft was in cruise flight when the engine suddenly ran rough, appeared to lose power, and then ran rough again. In response to the engine issues, the pilot applied carburetor heat and switched fuel tanks, but these actions produced no significant effect on the engine's performance.
The pilot subsequently performed a forced landing into tall grass within a barley field. During the landing sequence, the aircraft nosed over. The impact resulted in damage to the propeller and caused the vertical fin and rudder to bend. There were no injuries reported.
The investigation
Following the accident, the aircraft was recovered to an airport. An FAA inspector conducted a test by starting the engine and operating it at an idle power setting. The investigation could not determine the specific reason for the partial loss of engine power.