What is the function of the auxiliary fuel pump in the fuel flow process?

The auxiliary fuel pump serves a crucial role in maintaining the proper fuel flow to the engine, especially during specific phases of flight such as engine start and low-speed operations. Its primary function is to boost fuel pressure, which ensures that the fuel reaches the engine at the correct pressure for efficient combustion.

When the engine is starting or operating at low throttle settings, the main fuel pump may not provide sufficient pressure on its own. The auxiliary pump kicks in to increase the fuel pressure, which helps prevent engine stall or failure. Additionally, in the event of a failure of the main pump, the auxiliary fuel pump acts as a backup to ensure that fuel continues flowing to the engine.

Understanding this function is vital for pilots, as it directly relates to engine performance and safety. In contrast, other options present functions that the auxiliary pump does not perform, such as shutting off fuel supply or draining excess fuel. The focus on boosting fuel pressure highlights the importance of reliable fuel delivery in sustaining engine operation.