Definition
A non-contact rotating seal used in turbine engines and other high-speed machinery, consisting of a series of thin ridges or fins on a rotating component that run very close to a stationary surface. Gas attempting to leak past the seal must pass through a winding, restrictive path of small chambers that progressively reduce its pressure and limit flow.
Plain English
A seal that controls leakage by forcing air or gas to squeeze through a long, twisting gap rather than blocking it directly. Because the parts never actually touch, it can spin at high speed without wearing out.
Context Anchor
Seen in powerplant maintenance discussions, especially around turbine engine shafts, bearing areas, and places where air or oil leakage must be controlled.
Derivation
From the Greek labyrinthos, meaning a maze or winding passage. The name fits because gas trying to escape is forced through a maze-like path that saps its pressure at every turn.
Why Pilots Care
Labyrinth seals control internal airflow and oil compartment pressurization in turbine engines. When they wear or fail, oil can migrate into hot sections or excessive air can leak between stages, causing oil consumption issues, smoke, or performance loss.
Intuition Check
Do not picture a soft gasket that tightly closes a gap by rubbing against a surface. A labyrinth seal usually controls leakage by creating a long, winding path with very small clearances.
Example Sentence 1
The technician inspected the labyrinth seal at the rear of the compressor for wear after noticing higher-than-normal oil consumption.
Example Sentence 2
The compressor section uses a labyrinth seal to keep oil from migrating into the airflow path.