Which component is driven by the main gearbox and provides mounting and drive for essential components such as hydraulic pumps, generators, rotor brake discs, etc?

• A. Accessory Gearboxes/Drives
• B. Tail gearbox
• C. Driveshaft sections
• D. Free-wheeling unit

Answer: (A)

The main idea is that a helicopter uses an accessory gearbox driven by the main gearbox to power and mount essential systems. This accessory gearbox acts as a central hub, providing the drive and mounting points for components like hydraulic pumps, electrical generators, and rotor brake discs. By taking power from the main gearbox, it keeps these critical subsystems organized in one location and sized for their required speeds.

The other options don’t fit this role: the tail gearbox drives the tail rotor, not the main-accessory equipment; driveshaft sections are simply the connections that transmit power, not the mounting and drive for accessories; and the free-wheeling unit allows autorotation or coast without engaging the engine, not a power source or mounting for essential systems.