Incident Overview
An airplane experienced a loss of engine power during an agricultural spraying operation, resulting in a forced landing that caused the aircraft to nose over. The pilot reported no injuries.
Pilot Statement
The pilot stated that at approximately 10:30 AM, as the spraying operation was nearing completion, while pulling out of the field being sprayed, the engine made a bang, started running very rough, and backfired. Within a couple of seconds, the engine had lost all power and died. The pilot landed in a field that happened to be very soft and sandy. The aircraft rolled approximately 100 feet on its wheels before nosing over onto its back.
Investigation Findings
After further investigation, it was determined that a rocker shaft housing had broken on the #4 cylinder. As a result, the exhaust valve was not opening. When the intake valve opened, it created backfiring into the induction system, causing the engine to fail.
Damage
The airplane sustained substantial damage from the forced landing and nosed-over event.