Definition
A soft, sacrificial liner fitted to the inside of a turbine engine casing directly opposite the rotating compressor or turbine blade tips. It is designed to wear away when contacted by the blade tips, allowing the engine to maintain the smallest possible clearance between the blades and the casing without causing damage to the blades themselves.
Plain English
A soft strip on the inside of an engine case that rubs away when the spinning blade tips touch it, keeping the gap between the blades and the case as small as possible.
Context Anchor
Seen in turbine engine maintenance when checking blade tip clearance, engine seals, or wear inside the engine case.
Derivation
From the verb 'abrade,' meaning to wear away by friction. The strip is built specifically to be abraded — sacrificed — so the harder, more expensive blade tips are not.
Why Pilots Care
Maintaining correct tip clearance improves engine efficiency, reduces fuel burn, and prevents blade tip damage or performance loss.
Grounding Statement
The strip is supposed to wear before the harder, more important blade tips are damaged.
Intuition Check
Do not assume a worn abradable strip is automatically a failed part. Its job is to be rubbed away within limits, but too much wear or uneven wear can signal a problem.
Example Sentence 1
During inspection, the technician checked the abradable strip for excessive wear and uneven rub patterns.
Example Sentence 2
After the abradable strip was replaced, the turbine blades maintained the designed clearance and the engine regained full performance.