Which component changes the direction of power flow from the intermediate gearbox to the tail rotor assembly?

• A. Tail rotor gearbox
• B. Main transmission
• C. Engine
• D. Hydraulic pump

Answer: (A)

Understanding how a helicopter redirects power to the tail rotor is essential. The tail rotor gearbox is the component that changes the direction of power flow from the intermediate gearbox to the tail rotor assembly. It receives power from the intermediate gearbox, reduces the speed to an appropriate level for the tail rotor, and reorients the rotation so the tail rotor spins in the opposite direction to the main rotor. This reversal creates the anti-torque force needed to counteract the main rotor’s torque and to provide yaw control. The engine is the power source, but it doesn’t change direction by itself. The main transmission drives the main rotor, not the tail rotor, and the hydraulic pump is part of the aircraft’s hydraulic system, not the tail-rotor drive.