Definition
A chemical fluid applied to the external surfaces of an aircraft on the ground to prevent the formation and adherence of frost, ice, or snow for a limited period of time before takeoff. It is typically a glycol-based mixture, often thickened, that lowers the freezing point of any moisture that contacts the treated surface and is designed to shear off the airframe during the takeoff roll.
Plain English
A liquid sprayed on a clean aircraft to stop ice or snow from sticking to it for a short window of time before takeoff.
Context Anchor
You encounter this term during cold-weather preflight planning and when an aircraft is sprayed on the parking area before departure.
Derivation
"Anti-" comes from Greek meaning "against," and "icing" refers to the formation of ice. The name reflects its purpose: it acts against ice forming in the first place, rather than removing ice already present.
Why Pilots Care
Ice accumulation on wings and control surfaces reduces lift, increases drag, and can lead to loss of control; anti-icing fluid provides proactive protection that maintains aerodynamic performance.
Intuition Check
Anti-icing fluid is not just any cold-weather liquid. It is used to prevent or delay ice buildup; removing ice that is already there is deicing.
Example Sentence 1
After the aircraft was deiced, the ground crew applied anti-icing fluid to protect the wings during the taxi to the runway.
Example Sentence 2
After a long ground delay the crew reapplied anti-icing fluid to maintain protection.