Accident Sequence
The airplane was climbing through 5,500 feet when the engine began to vibrate and lose power. The pilot observed an increase in oil temperature and a decrease in oil pressure, followed by a total loss of engine power. The pilot executed a forced landing to a field; however, during the landing, the airplane's left wing impacted a tree.
Post-Accident Examination
Examination of the airplane revealed streaks of oil on the engine cowling and a 6-inch hole in the top of the engine crankcase, in the vicinity of the number 2 cylinder. Further examination showed that the number 2 connecting rod was broken into four pieces. The connecting rod journal was black in color and the metal had a "smeared" appearance. Fretting was observed on the mating surfaces of the number 2 main bearing saddles. Additionally, the bearing shells had "walked" towards the rear of the engine about 1/4 of an inch. The crankcase through-bolt torques could not be determined.
Engine History
According to a representative of the engine manufacturer, a bearing shift could result in a decrease in oil flow to the journal, and a subsequent catastrophic engine failure. The airplane had been operated for 26 hours since its most recent annual inspection, which was performed about a month prior to the accident. The engine had been operated for about 1,700 hours since it was rebuilt by TCM about 9 years prior to the accident. The number 2 and 4 cylinders had been replaced about 830 hours prior to the accident.