Definition
A chamber within a turbine engine's lubrication system where air is separated from the scavenged oil before the oil returns to the tank. Hot oil leaving the bearings is mixed with air, and the deaerator chamber removes that air so the oil can be recirculated efficiently and without foaming.
Plain English
A small section in the engine's oil system that takes the air bubbles out of the oil before it goes back to the tank to be used again.
Context Anchor
Seen in aircraft engine lubrication system descriptions, especially oil tank and oil return flow discussions.
Derivation
From 'de-' meaning 'remove' and 'aerate' meaning 'to mix with air.' A deaerator literally undoes the aeration -- it pulls the air back out of the oil.
Why Pilots Care
Prevents vapor lock and erratic fuel flow that could cause engine roughness or power loss during flight.
Grounding Statement
After oil returns to the tank with air bubbles mixed in, the deaerator chamber gives the air a place to separate out before the oil is used again.
Intuition Check
Do not read “deaerator” as something that adds air. In this term, it means the chamber removes air from the oil.
Example Sentence 1
After passing through the bearings, the foamy oil is routed to the deaerator chamber, where the air is separated before the oil returns to the tank.
Example Sentence 2
Fuel flows from the tank through the deaerator chamber before reaching the engine-driven fuel pump.