NOT a listed trigger for the electrical fuel boost pumps to activate?

NOT a listed trigger for the electrical fuel boost pumps to activate?

• A. Low Pressure
• B. Engine Start
• C. APU Start
• D. Normal Operation

Answer: (D)

The main idea here is that electrical fuel boost pumps exist to guarantee fuel supply when the normal feed isn’t enough. They’re part of a redundancy scheme that keeps engines and the APU fed even if the primary pumps can’t keep up. They activate during start sequences and whenever feed pressure drops. Specifically, during engine start they’re used to prime the fuel lines so the engine can light off reliably, and during APU start they help deliver fuel to the APU. They also come on automatically if a low-pressure condition is detected in the fuel feed, preventing fuel starvation in the system. In normal operation, the engine-driven pumps usually provide adequate pressure and flow, so there’s no need for the boost pumps to run. That’s why normal operation isn’t a trigger for activating the electrical boost pumps.

The main idea here is that electrical fuel boost pumps exist to guarantee fuel supply when the normal feed isn’t enough. They’re part of a redundancy scheme that keeps engines and the APU fed even if the primary pumps can’t keep up.

They activate during start sequences and whenever feed pressure drops. Specifically, during engine start they’re used to prime the fuel lines so the engine can light off reliably, and during APU start they help deliver fuel to the APU. They also come on automatically if a low-pressure condition is detected in the fuel feed, preventing fuel starvation in the system.

In normal operation, the engine-driven pumps usually provide adequate pressure and flow, so there’s no need for the boost pumps to run. That’s why normal operation isn’t a trigger for activating the electrical boost pumps.