Which component is centrally located and transmits power from the engine to the main and tail rotor drive systems at a reduced rate?

• A. Main gearbox/Main Transmission
• B. Tail gearbox
• C. Intermediate gear box
• D. Accessory Gearboxes/Drives

Answer: (A)

Power transmission from the engine to the rotor systems is handled by a central gear reduction unit located between the engine and the rotor masts. This main gearbox reduces the engine’s high RPM to the much slower RPM needed by the main rotor, while also providing the drive path to the tail rotor through the connected drive system. Its central placement is what makes it the hub for powering both rotors at the required reduced rates. The tail gearbox, by contrast, sits at the tail and drives only the tail rotor; an intermediate gearbox may exist in some layouts but isn’t the primary link to both rotors; and accessory gearboxes drive non-rotor systems like generators and hydraulic pumps.