Incident Details
While in cruise flight, the pilot noticed smoke emanating from the engine and entering the cockpit. The pilot secured the engine and executed a forced landing to a field. During the forced landing, the airplane impacted a fence, trees, and came to rest upright.
Engine Examination
Examination of the engine revealed the number six cylinder was partially separated from the crankcase, and several of the cylinder fasteners, deck studs and through-bolts, were fractured. Metallurgical examination of the fracture surfaces by the manufacturer revealed evidence of fatigue and overload signatures. Fretting was noted on the cylinder and crankcase mating surfaces. Hardness of each of the deck studs and through-bolts met manufacturer's specifications. No additional anomalies were noted with the engine that would have precluded normal operation.