What happened
The incident began during the departure climb phase of flight when the aircraft's engine failed. The pilot attempted to restart the powerplant but was unsuccessful. With no alternative options available, the pilot executed a forced landing into an adjacent field. Upon touchdown, the nose gear became bogged down in the soft soil, causing the aircraft to nosed over.
The investigation
Following the accident, investigators disassembled and examined the powerplant. During this process, a fracture was discovered on the crankshaft between the number one and two cylinder journals. Review of the airframe and engine logbooks indicated that the crankshaft had been installed on March 28, 1984, during an engine overhaul. At the time of the accident, the aircraft had accumulated only 54 flight hours since that overhaul. It could not be determined whether the crankshaft was new or reconditioned when it was originally installed.
Findings
The primary mechanical failure was a fractured crankshaft. The subsequent nosing over was caused by the nose gear becoming bogged in soft soil during the forced landing.