Definition
A fuel pump mounted on and mechanically driven by the airplane's engine that supplies fuel under pressure from the tanks to the carburetor or fuel injection system whenever the engine is running. It is the primary fuel pump in airplanes that require pressurized fuel delivery, and is typically backed up by a separate electric (auxiliary or boost) pump.
Plain English
A pump that runs off the engine itself and pushes fuel from the tanks to the engine while the engine is turning. It is the main fuel pump, and there is usually a backup electric pump in case it fails.
Context Anchor
Seen in fuel-system descriptions, engine starting procedures, and checklists for low fuel pressure or engine roughness.
Why Pilots Care
It is the main source of fuel pressure in most light aircraft; pilots rely on it for normal flight and must know backup procedures if it fails.
Intuition Check
Engine-driven does not mean the pump controls the engine. It means the engine powers the pump; if the engine stops turning, this pump no longer provides its normal fuel pressure.
Example Sentence 1
Before takeoff, the pilot switched on the auxiliary fuel pump as a backup in case the engine-driven fuel pump failed during the climb.
Example Sentence 2
After an engine-driven fuel pump failure the pilot switched on the electric boost pump to restore fuel flow.