What happened
Following a routine preflight inspection, engine start, and taxi, the aircraft departed the runway without incident. During the climb phase, at an altitude between 1,000 and 1,500 feet, the pilot observed the engine power decreasing in a smooth and gradual manner. The pilot described the sensation as a loss of torque or the propeller transitioning into a feathered position. In response to the power loss, the pilot executed an emergency forced landing into a nearby field. Upon impact, the aircraft nosed over and came to rest in an inverted position.
Findings
Post-accident inspections of the engine and propeller assembly identified mechanical discrepancies in the propeller control mechanism. Specifically, the propeller-reversing lever had been incorrectly positioned on the wrong side of the reversing lever guide pin. Additionally, the carbon block within the reversing linkage was missing from the assembly, having departed the aircraft during operation.
Maintenance records indicated that this carbon block had been replaced during a 100-hour inspection just five hours before the flight. The investigation concluded that the incorrect installation of the reversing lever caused the carbon block to seat improperly, leading to accelerated wear and its eventual detachment. According to the engine manufacturer, any disruption in the propeller control linkage causes the beta control valve to extend, which forces the propeller into a feathered state.