Definition
An electrically driven auxiliary fuel pump that supplies pressurized fuel from the tank to the engine, supplementing or backing up the engine-driven fuel pump. It is used during engine start, takeoff, landing, switching tanks, and high-altitude operations, or any time positive fuel pressure is required to prevent vapor lock or fuel starvation.
Plain English
An extra fuel pump, run by electricity, that pushes fuel from the tank to the engine. It helps during start-up and certain phases of flight, and it acts as a backup if the main fuel pump on the engine fails.
Context Anchor
You will see this term in fuel system discussions, aircraft checklists, and procedures for starting, takeoff, landing, and abnormal fuel pressure indications.
Derivation
From 'boost,' meaning to give extra push or lift. The pump 'boosts' fuel pressure beyond what the engine-driven pump alone provides, or supplies pressure when that pump is not yet running.
Why Pilots Care
Maintains reliable fuel flow during critical phases and supplies redundancy against engine-driven pump failure, reducing the risk of fuel starvation or vapor lock.
Intuition Check
Do not read boost pump as a pump that gives the airplane extra speed or power. Here, boost means added help for fuel pressure or fuel flow to the engine.
Example Sentence 1
Before starting the engine, the pilot turned on the boost pump and watched the fuel pressure rise into the green arc.
Example Sentence 2
During the approach, the boost pump was turned on as a precaution in case of low fuel pressure.