How many engine-driven fuel pumps are needed per engine for those requiring fuel pumps?

Each engine requiring fuel pumps typically has one engine-driven fuel pump. This design choice helps maintain a sufficient supply of fuel under various operating conditions while also simplifying the system.

Having one pump per engine ensures that there is a reliable and consistent fuel flow necessary for optimal engine performance. In most aircraft, this single pump is designed to be robust and capable of handling the demands of delivering fuel directly to the engine's fuel control system. While some advanced systems might incorporate additional pumps for redundancy or special operational scenarios, the standard practice in most general aviation and commercial aircraft is to use one engine-driven fuel pump per engine.

This allows for efficient functioning without unnecessary complexity, minimizing potential points of failure while ensuring that each engine receives the proper fuel to operate effectively.