Accident Description
The aircraft experienced an engine failure while in cruise flight, leading to a forced landing off the airport. During the landing, the aircraft nosed over.
Engine Examination
The engine was disassembled and examined on December 3, 1984. The examination revealed that the #3 and #4 piston rods had separated from their crankshaft journals. Most of the rod bearings were found to be worn.
Oil and Operating Conditions
The aircraft had been operating in an environment with cold winters. According to the engine operations manual, SAE 30 weight oil or 10W-30 is recommended for operations in temperatures below 40 degrees Fahrenheit. However, the engine had been serviced with 40 weight oil during the last several servicings. The temperature on the day of the accident was below 40 degrees Fahrenheit.