Definition
A turbine blade design feature in which the very tip of the blade is made thinner than the rest of the blade, so that if the blade rubs against the engine's outer shroud during operation, the thin tip wears away (or 'squeals') without damaging the blade body or the surrounding case.
Plain English
A deliberately thin edge built into the top of a turbine blade. If the blade ever touches the engine wall while spinning, only that thin edge wears down — the main blade and the engine stay safe.
Context Anchor
Seen in turbine engine maintenance, especially during inspection of turbine blade tips, blade-tip wear, and engine gas-path sealing.
Derivation
The name comes from the high-pitched squealing sound a blade tip can make when it briefly contacts the shroud at high speed. The thin tip is designed to be the sacrificial part that makes the noise and wears away, rather than causing damage.
Why Pilots Care
For maintenance technicians, the condition of the squealer tip is a direct indicator of how closely the blade has been running to the shroud and whether the engine has experienced excessive rubbing. Worn or damaged squealer tips can affect engine efficiency and may signal a developing problem.
Analogy
A squealer tip is like the raised rim around a shallow tray. The rim helps contain what is inside and is the first part to touch if something rubs against the tray’s edge.
Intuition Check
Do not read “squealer” as meaning a warning horn or cockpit noise. Here it means a raised blade-tip feature that may rub and help seal the gas path.
Example Sentence 1
During the borescope inspection, the technician noted slight wear on the squealer tips of several high-pressure turbine blades.
Example Sentence 2
Squealer tips help maintain tight clearances inside the turbine without allowing excessive air leakage.