Definition
A mechanical air pump mounted on and driven by the aircraft engine, using a rotor with sliding vanes inside an offset chamber to produce the suction or pressure airflow that powers air-driven gyroscopic instruments. As the rotor turns, the vanes slide in and out to maintain contact with the chamber wall, drawing air in on one side and expelling it on the other. It has replaced the older venturi system in most modern aircraft because it works on the ground and at all airspeeds.
Plain English
A small pump turned by the engine that moves air through the system that spins certain flight instruments. It uses spinning blades that slide in and out to push the air along.
Context Anchor
Seen in discussions of vacuum or pressure systems that power gyroscopic flight instruments, especially in airplanes that use engine-powered instrument air instead of electric power for those instruments.
Derivation
‘Vane’ comes from Old English ‘fana’, meaning a flag or blade — here referring to the flat sliding blades inside the pump. ‘Engine-driven’ simply means the pump is turned by the aircraft engine rather than by airflow or an electric motor. Knowing this helps the pilot picture a bladed rotor spinning whenever the engine is running.
Why Pilots Care
Provides reliable vacuum power for primary gyro instruments without depending on the electrical system.
Intuition Check
Do not read pump here as a fuel pump or oil pump. In this chapter, it is moving air to power flight instruments, and engine-driven means the engine must be running for it to work normally.
Example Sentence 1
During the runup, the pilot checked the suction gauge to confirm the vane-type engine-driven pump was producing the required airflow for the gyro instruments.
Example Sentence 2
During the preflight check the pilot verifies that the suction gauge shows normal output from the vane-type engine-driven pump.