Definition
A device that uses a high-velocity jet of fluid or gas flowing through a venturi to create a low-pressure region, drawing a secondary fluid or gas along with it. In aircraft systems, ejectors are commonly used to scavenge fuel from tank sumps, transfer fuel between tanks, or remove air and vapors from fluid lines.
Plain English
A simple pump with no moving parts. A fast stream of one fluid rushing past an opening creates suction that pulls another fluid along with it.
Context Anchor
Seen in aircraft maintenance discussions of fuel, oil, vacuum, and ventilation systems.
Derivation
From the Latin 'ejectus,' meaning 'thrown out.' The name reflects how the device throws one fluid forward at high speed, which in turn pulls a second fluid out of where it's sitting.
Why Pilots Care
If an ejector is blocked, damaged, or not supplied with the needed flow, the system may not move fuel, oil, air, or vapor the way it is designed to.
Analogy
Like the suction created when you blow hard across the top of a drinking straw sitting in water — the fast-moving air pulls the water up the straw. An ejector works on the same principle, but built into a fluid line.
Intuition Check
Do not assume an ejector is only something that throws a person or object out. In aircraft systems, an ejector is often a no-moving-parts device that uses one flow to pull or move another flow.
Example Sentence 1
The fuel system uses an ejector to scavenge residual fuel from the bottom of the tank and return it to the main supply line.
Example Sentence 2
The mechanic inspected the ejector in the vacuum pump line for any blockage that would reduce suction.