Definition
A visible crease, ridge, or buckle in a sheet metal aircraft skin or structural member, typically caused by compression loads, impact damage, or improper repair. A wrinkle indicates the material has yielded beyond its elastic limit and may signal hidden structural damage in the underlying framework.
Plain English
A small fold or ripple in the metal skin of an aircraft. It usually means the metal has been pushed or bent harder than it can spring back from, and there may be more damage underneath that you can't see.
Context Anchor
Seen during preflight inspections, maintenance checks, and inspections of aircraft skin, fabric covering, control surfaces, or panels.
Derivation
Wrinkle comes from older English words meaning a fold, twist, or uneven line in a surface. That origin fits the aviation use: the surface is no longer lying flat and smooth.
Why Pilots Care
Wrinkles can reduce aerodynamic efficiency, signal fabric loosening that affects flight characteristics, or indicate structural problems needing immediate maintenance.
Analogy
A sheet of paper can form a wrinkle when it is pushed from the ends. Aircraft material can show a similar fold or wave when it has been stressed, though the aircraft cause must be inspected rather than guessed at.
Intuition Check
Do not assume a wrinkle is only cosmetic, like a wrinkle in clothing. On an aircraft, a wrinkle can be a clue that the surface has been bent, loaded, or damaged.
Example Sentence 1
During preflight, the pilot noticed a wrinkle in the skin near the wing root and grounded the aircraft for inspection.
Example Sentence 2
Any new wrinkle found near a wing rib during inspection requires checking fabric tension and rib condition.