Incident Details
The pilot reported that after the airplane reached an altitude of 10,500 feet mean sea level (MSL), the skydivers exited. Following their exit, the pilot initiated a wings-level, high-rate descent to remain clear of the drop zone. During the descent, the mixture was set to full rich and carburetor heat was applied. The pilot maintained an indicated airspeed between 150 and 160 knots, with power set at 21 to 22 inches of manifold pressure and propeller speed at 2200 to 2300 RPM.
At approximately 6,000 feet MSL, the airplane's engine surged and began to run rough. The pilot decided to perform a forced landing in a field after determining that the airplane would not be able to reach the airport. During the landing, the nose wheel struck a berm, causing the airplane to nose over.
Post-Accident Findings
After the accident, the airplane's engine was successfully started and run. It operated normally with no observed mechanical anomalies.
Aircraft Manual Guidance
The airplane operator's handbook stated that application of full carburetor heat may enrichen the mixture to the point of engine roughness.