What happened
The pilot was conducting an agricultural application flight when the incident occurred. During a pull-up and turnaround maneuver at the conclusion of a swath run, the engine began emitting smoke and subsequently lost power. In response to the emergency, the pilot jettisoned the chemical load to reduce weight and executed a forced landing in a field characterized by vegetation approximately 6 to 8 feet tall.
After initial contact with the ground, the aircraft traveled approximately 100 feet before nosing over. The flight phase at the time of failure was identified as maneuvering during agricultural operations.
The investigation
A post-accident inspection of the engine revealed significant mechanical failure. The examination determined that the impeller bearing had failed. This failure allowed the impeller to come into contact with the rear casing of the engine, which led to the loss of power and the subsequent smoke observed by the pilot.
Findings
The investigation identified the mechanical failure of the impeller bearing as the primary factor in the accident sequence. The contact between the impeller and the rear casing resulted in total engine power loss during a critical phase of flight.