What maintains fuel pressure during operation?

The maintenance of fuel pressure during operation is primarily achieved through scavenge ejector pumps. These pumps are designed to remove fuel from the fuel tanks and ensure that it is delivered to the engine at the appropriate pressure. They play a crucial role in the fuel system by effectively managing the flow and maintaining consistent pressure, which is essential for optimal engine performance.

Scavenge ejector pumps utilize a venturi effect, wherein fuel flows through a constricted passage that creates a pressure drop, allowing them to draw fuel from the tank while maintaining the necessary pressure for delivery. This process ensures that the fuel system operates efficiently and that fuel is readily available to the engine when needed.

Other options such as fuel return lines, fuel transfer pumps, and vacuum systems serve different functions in the overall fuel management system but are not primarily responsible for maintaining the necessary fuel pressure during engine operation. Fuel return lines help return excess fuel back to the tank, fuel transfer pumps are typically involved in moving fuel between tank compartments, and vacuum systems assist with other components rather than directly influencing fuel pressure.