Engine Vibration and Power Loss Leads to Forced Landing (N23820)

Incident Summary

During cruise flight, the airplane's engine began to vibrate and lose power. The pilot was unable to maintain altitude and performed a forced landing to a field.

Engine Examination

The airplane was equipped with a Pratt and Whitney R1340 radial engine. Examination of the engine revealed that approximately 50 percent of the number eight cylinder head was separated from its respective cylinder barrel.

Maintenance Records

Review of maintenance records showed that the engine had been operated for about 930 hours since it was last overhauled and about 20 hours since its most recent annual inspection. At the time of the annual inspection, a mechanic reported he examined the cylinders and did not detect any cracks.