What is the purpose of an unfeathering accumulator?

The purpose of an unfeathering accumulator is to provide oil pressure necessary to unfeather a propeller. In multi-engine aircraft, particularly those equipped with feathering propellers, the unfeathering accumulator plays a crucial role. When an engine is shut down, the propeller blades can be feathered to reduce drag. When it is time to restart the engine, the propeller needs to be unfeathered, and this is done by using the oil pressure supplied from the unfeathering accumulator.

This accumulator is charged with hydraulic fluid at system pressure while the engine is running. When the propeller needs to be unfeathered, the fluid from the accumulator is directed to the propeller's unfeathering mechanism, enabling it to resume a normal operating position. This process is essential for ensuring that the propeller is ready to produce thrust efficiently during engine start and operation, enhancing the safety and performance of the aircraft.

Other options do not address the specific function of an unfeathering accumulator. Storing fuel for engine start is unrelated to the propeller's operation. Maintaining oil temperature involves different systems and components, not directly related to the unfeathering process. Controlling blade pitch pertains to propeller