Definition
The shaped surfaces of an aircraft that are designed to produce aerodynamic forces when air flows over them — primarily the wings, horizontal stabilizer, vertical stabilizer, and propeller blades. Each of these surfaces has a curved cross-sectional shape (an airfoil) that generates lift, control authority, or thrust as air moves across it.
Plain English
The shaped parts of the airplane that air flows over to produce lift or control — the wings, the tail surfaces, and the propeller blades.
Context Anchor
You will see this term in discussions of ice protection on wings, tail surfaces, and other shaped aircraft surfaces exposed to icing conditions.
Derivation
‘Airfoil’ comes from ‘air’ plus ‘foil,’ where foil originally meant a thin shaped sheet (from Old French ‘foille,’ leaf). An airfoil is a shape designed to work against the air. ‘Section’ refers to the cross-sectional shape of that surface — what you would see if you sliced through a wing.
Why Pilots Care
Ice on airfoil sections alters their shape, reduces lift, and can cause control problems; keeping these areas clear is essential for safe flight in icing conditions.
Intuition Check
Do not read “sections” as sections of a book or manual here. In this context, “airfoil sections” means physical shaped parts of the aircraft, especially wing or tail areas exposed to airflow.
Example Sentence 1
Before flight in cold weather, the pilot inspected all airfoil sections for frost or ice accumulation.
Example Sentence 2
Heated elements protect the leading-edge airfoil sections on the wing and horizontal stabilizer.