What is the function of the electric boost pump in a fuel system?

The electric boost pump in a fuel system is primarily designed to ensure a continuous flow of fuel to the engine, especially during critical phases of flight such as starting the engine and during takeoff. It "sucks" fuel from the tank and helps maintain the required fuel pressure. This is particularly important in multi-engine aircraft where fuel flow must be reliable to prevent engine flameouts.

During engine start, the electric boost pump ensures that fuel is readily available to the engines, overcoming any potential issues with fuel line pressure or obstructive fuel pathways. Additionally, when the aircraft is operating at low fuel levels or when the main engine-driven fuel pump fails, the electric boost pump is crucial for providing the necessary fuel supply.

The other options pertain to different systems and features. For example, increasing hydraulic pressure for landing gear is not the function of the boost pump but rather the hydraulic system itself. Providing backup power during engine failure relates to redundant power systems, not fuel delivery. Pressurizing fuel tanks before takeoff is not typically within the function of a boost pump but may relate more to maintaining specific conditions for fuel vapor management. Thus, focusing on the role of the electric boost pump emphasizes its purpose of facilitating effective fuel supply to the engines.