Which symptom suggests uncommanded propeller feathering?

Uncommanded propeller feathering occurs when the propeller moves towards the feathered position without a command from the pilot. This situation can present noticeable symptoms during flight operations.

Rapid loss of power is a significant symptom associated with uncommanded propeller feathering. When a propeller feathers, its blades sweep back, reducing drag and thrust, which translates to a sudden decrease in engine power or performance.

High torque is another potential indication of uncommanded feathering. If one propeller feathers while the other remains operational, the engine that is still functioning may experience increased torque to maintain control, presenting a challenge for the pilot.

Lower Np, which refers to a decrease in the propeller speed, is a direct consequence of feathering. As the propeller blades move into the feathered position, the rotational speed of the propeller decreases, which can easily be observed on the cockpit instruments.

Given that all three symptoms—rapid loss of power, high torque, and lower Np—can point towards uncommanded propeller feathering, selecting the option that encompasses all these symptoms is indeed the most accurate response. This understanding emphasizes the interconnectedness of the symptoms that arise from uncommanded feathering and helps pilots to recognize and diagnose potential