What happened
The incident occurred while the aircraft was engaged in a banner towing operation. Shortly after departing from the airfield, the pilot reported experiencing a sudden loss of engine power. With the aircraft at a low altitude and lacking sufficient thrust to maintain flight or execute a return to the departure airport, the pilot made the decision to perform an emergency water landing. The aircraft was successfully ditched in a nearby creek without further incident.
The investigation
Following the recovery of the aircraft, a detailed mechanical examination of the engine was conducted to determine the root cause of the power failure. The inspection revealed that the number two exhaust valve had failed. Maintenance records indicated that the engine had accumulated a total operating time of 3,775 hours. Notably, only 1,366 hours had been flown since the engine underwent its last complete overhaul.
Findings
The investigation identified engine failure as the primary factor leading to the accident. The specific mechanical fault was traced to the failure of the number two exhaust valve (part number 75068). The relatively low time-in-service since the last overhaul suggests that the component may have failed prematurely or due to wear not immediately apparent in routine checks. The pilot's decision to ditch in a creek was a direct result of the inability to maintain altitude with the compromised engine.
Safety message
This event highlights the critical importance of regular engine inspections and adherence to overhaul intervals, particularly for engines subjected to the high-stress conditions typical of banner towing operations.