Definition
A form of surface damage on engine components caused by metal-to-metal contact between two moving parts when the lubricating oil film breaks down. The result is small areas of welding and tearing where the surfaces briefly stick and then pull apart, leaving rough, smeared marks on what should be smooth bearing or sliding surfaces.
Plain English
Damage to engine parts that happens when two metal surfaces rub together without enough oil between them. The metal briefly sticks in tiny spots and tears away, leaving the surface roughed up instead of smooth.
Context Anchor
Seen during engine maintenance inspections, especially when checking parts such as cylinder walls, pistons, shafts, bearings, or gears for wear damage.
Derivation
From the everyday verb 'scuff,' meaning to scrape or mark a surface by rubbing. In engine work, it refers to the same idea but on a microscopic scale — metal surfaces scraping each other hard enough to cause damage.
Why Pilots Care
Unchecked scuffing signals lubrication problems that can progress to scoring, seizure, or engine failure.
Analogy
Like the rough marks left on a shoe sole after it drags across concrete.
Intuition Check
Do not think of scuffing as just a cosmetic scratch. In aircraft engine maintenance, scuffing usually means harmful metal-to-metal rubbing has occurred.
Example Sentence 1
During inspection, the mechanic found scuffing on the cylinder walls, indicating the engine had been run with insufficient oil pressure.
Example Sentence 2
Early scuffing in the bore can cause higher oil use and reduced compression.