Incident Overview
During the downwind leg of the traffic pattern, the airplane's engine began to misfire. The pilot applied carburetor heat and increased engine power to 1,500 RPM, but the misfiring persisted. Despite further increases in power, engine performance did not improve.
Emergency Landing
On the base leg, the pilot turned off the carburetor heat and reduced engine power to idle in preparation to land. At this point, the engine ceased producing power entirely. The pilot executed a shallow right turn and aligned with a field for an emergency landing. The pilot was aware of power lines preceding the field and flew beneath them. However, the right main landing gear contacted a small tree and was sheared off. The airplane landed in the field and ground-looped.
Post-Incident Examination
The aircraft had a sufficient quantity of fuel onboard, and the fuel was free of debris and contamination. The engine was run on the airframe using the airplane's own fuel system; it started immediately and operated normally. Examination of the airplane and engine revealed no mechanical malfunctions.