Definition
An air pump mounted on and driven by the aircraft engine, used to supply the suction or pressure needed to operate air-driven flight instruments such as the attitude indicator and heading indicator, and in some installations to power deicing boots or other pneumatic systems. Most modern engine-driven air pumps are dry vane pumps, using carbon vanes that require no lubrication.
Plain English
A small pump bolted to the engine that spins whenever the engine runs. It moves air through the system that powers certain cockpit instruments, and sometimes other equipment that needs air pressure or suction.
Context Anchor
You may see this term in preflight checks, maintenance records, and instrument-system descriptions, especially when checking whether the aircraft has normal suction or vacuum indication.
Why Pilots Care
If the pump fails, the attitude indicator and directional gyro stop working, forcing the pilot onto partial-panel instruments or backup systems.
Intuition Check
Do not assume this is an electric backup pump. Engine-driven means the pump depends on the engine turning.
Example Sentence 1
During the runup, the pilot checked the suction gauge to confirm the engine-driven air pump was producing normal vacuum for the gyro instruments.
Example Sentence 2
The preflight checklist requires confirming that the engine-driven air pump is producing normal suction before takeoff.