What drives the engine accessory gearbox?

• A. Power turbine
• B. Gas generator turbine
• C. Compressor turbine
• D. Transmission output

Answer: (B)

The engine accessory gearbox is primarily driven by the gas generator turbine. This component of the engine is responsible for producing the necessary power to drive various accessories such as the alternator, fuel pumps, and hydraulic pumps. When the gas generator turbine operates, it spins at high speeds due to the combustion process, and this rotational energy is transmitted to the accessory gearbox.

The gas generator turbine works in conjunction with the combustion chamber and compressor sections of the engine, and it is crucial for sustaining the operational characteristics of the helicopter engines, such as maintaining the required speed and efficiency. The accessory gearbox then utilizes this power to operate the essential systems of the aircraft, ensuring optimal performance of the helicopter's functions.

In contrast, other components mentioned, like the power turbine, compressor turbine, and transmission output, do not directly drive the accessory gearbox. The power turbine generally relates to the portion of the engine that converts energy into usable power for propulsion, while the compressor turbine is focused on airflow management in the engine. The transmission output pertains to how power is delivered to the rotor system or other components, but it is separate from the operations of the accessory gearbox directly driven by the gas generator turbine.