In flight, what enables a feathering propeller to move to the feather position when oil pressure is removed?

In flight, what enables a feathering propeller to move to the feather position when oil pressure is removed?

• A. Aerodynamic forces keep the propeller rotating fast enough that centrifugal force holds the blades unlatched so they can move to the feather position when oil pressure is taken out of the propeller.
• B. Oil pressure automatically increases to feather
• C. The blades are manually re-sequenced
• D. The propeller locks and cannot move to feather

Answer: (A)

When oil pressure is removed, a feathering prop relies on windmilling and centrifugal forces to move the blades to the high-pitch (feather) position. In flight, the propeller continues to spin because of the airflow, and the centrifugal force acting on the pitch-change mechanism helps release or unlatch the system. With the hydraulic bias gone, the mechanism can be driven toward feather by its spring/counterweight arrangement, so the blades rotate to a position that minimizes drag. The aerodynamic wind and the centrifugal unloading together let the blades reach and stay in the feathered state until oil pressure is restored or the engine is shut down.

When oil pressure is removed, a feathering prop relies on windmilling and centrifugal forces to move the blades to the high-pitch (feather) position. In flight, the propeller continues to spin because of the airflow, and the centrifugal force acting on the pitch-change mechanism helps release or unlatch the system. With the hydraulic bias gone, the mechanism can be driven toward feather by its spring/counterweight arrangement, so the blades rotate to a position that minimizes drag. The aerodynamic wind and the centrifugal unloading together let the blades reach and stay in the feathered state until oil pressure is restored or the engine is shut down.