Which component is NOT part of the accessory drive section in an APU?

The gas turbine assembly is not part of the accessory drive section in an Auxiliary Power Unit (APU). The accessory drive section primarily encompasses components like the starter motor, oil cooler fan, and fuel control unit, which are essential for the operation and functionality of the APU beyond the core engine components.

The gas turbine assembly is a critical part of the APU, but it primarily relates to the main engine operation rather than the accessory drive. The accessory drive is responsible for powering various auxiliary systems and accessories that support the APU's operation, facilitating functions such as starting the engine and managing fuel flow, but it does not include the core assembly of the gas turbine itself. Understanding the differentiation between these components is crucial for recognizing how APUs function and the organization of their systems.