The aft supporting structure is associated with which subsystem?

• A. Reduction Gearbox
• B. Accessory Gearbox
• C. Gas Generator
• D. Power Turbine

Answer: (A)

The rear, or aft, supporting structure is the strong frame that carries the heavy hardware mounted at the back of the engine. The reduction gearbox sits on this aft frame and is built to transfer the high-speed power from the turbine to the driven shaft while enduring torque and weight. Because the gearbox is a large, load-bearing component that must stay precisely aligned with the power train, it requires the aft structure to provide rigid support and proper mounting. The gas generator is the core of the engine and is supported along the core frames, not primarily by the aft structure. The accessory gearbox is mounted away from the extreme aft and is driven from the core for pumps and accessories, rather than being the main rear-load component. The power turbine is connected to the gearbox, but the aft structure’s role is to support the gearbox itself. Therefore, the subsystem associated with the aft supporting structure is the reduction gearbox.