What happened
The pilot reported that an agricultural airplane was executing a turn for its second pass over a designated field when the engine began to flutter and lose power. In response, the pilot advanced the engine controls to full power; however, the tachometer indicated that the engine speed remained low at approximately 1,500-1,600 RPM.
Recognizing the inability to maintain altitude or continue the mission, the pilot jettisoned the agricultural load and configured the aircraft for a forced landing within the field. Upon touchdown, the airplane encountered a slope in the terrain, which caused the nose to pitch down. The aircraft nosed over and came to rest in an inverted position.
The investigation
A thorough examination was conducted to determine the mechanical status of the engine and airframe following the incident. Investigators analyzed the engine components and fuel system for signs of failure or contamination. Despite these efforts, the specific mechanical reason for the loss of engine power could not be determined from the available evidence.
Findings
The investigation revealed that the agricultural airplane experienced an unexplained loss of engine power during flight. The pilot's decision to dump the load was appropriate for the emergency situation. However, the presence of a slope at the landing site contributed to the nose-over and subsequent inversion of the aircraft.
The cause of the initial power loss remains undetermined due to insufficient evidence to identify a specific mechanical failure mode.