Definition
Any foreign material on a wing's surface — such as ice, frost, snow, water, dirt, or insects — that disrupts the smooth airflow over the wing and degrades its ability to produce lift. Even a thin, rough layer can significantly increase stall speed, reduce maximum lift, and cause the wing to stall at a lower angle of attack than normal.
Plain English
Anything stuck to the wing that shouldn't be there. Even a small amount of frost, ice, or grime changes how air flows over the wing and makes the airplane harder to fly safely.
Context Anchor
Pilots encounter this during preflight inspection, in icing or frost conditions, and when reading about stalls, takeoff performance, and angle of attack indications.
Derivation
Contamination comes from the Latin contaminare, meaning 'to make impure by contact.' In aviation it keeps that core idea: the wing's clean aerodynamic surface has been spoiled by something foreign sitting on it.
Why Pilots Care
Even a thin layer of contamination can raise stall speed and reduce lift, creating an unexpected early stall during takeoff or landing.
Grounding Statement
A wing that looks only lightly frosted can still have enough surface roughness to disturb the airflow and reduce its ability to lift the airplane.
Intuition Check
Wing contamination does not only mean a large buildup of ice or obvious damage. In this FAA context, it means any unwanted material on the wing surface that can affect airflow, even if it looks minor.
Example Sentence 1
Before the first flight of the cold morning, the pilot checked carefully for wing contamination and brushed a thin layer of frost off both wings.
Example Sentence 2
Wing contamination from overnight frost required de-icing before the aircraft could safely depart.