Which component assists with engine starting in the APU system?

The ignition control unit plays a crucial role in the engine starting process within the Auxiliary Power Unit (APU) system. Its primary function is to provide the necessary spark to ignite the fuel-air mixture in the combustion chamber of the APU, which is essential for starting the engine. When the APU is initiated, the ignition control unit activates at the appropriate time to ensure that the engine starts efficiently and reliably.

The ignition control unit is specifically designed to handle the complexities of the ignition system, making it an integral part of the starting process. Its operation ensures that the electrical system and the fuel system are synchronized, providing a controlled start while preventing potential issues such as backfire or incomplete combustion.

In the context of the other components, while they perform important functions within the aircraft systems, they do not directly assist with engine starting in the APU. The fuel management system regulates the fuel supply, the throttle position sensor monitors throttle position for performance, and the oil pressure regulator manages oil flow and pressure, but none play the direct role of providing ignition necessary to start the engine.