Definition
Aircraft systems and devices designed to remove ice that has already formed on aircraft surfaces during flight or on the ground. Common types include pneumatic boots on wing and tail leading edges that inflate to crack and shed accumulated ice, and ground-applied chemical fluids that melt existing ice and snow before takeoff.
Plain English
Equipment that gets rid of ice that has already built up on the aircraft. It works after ice has formed, breaking it off or melting it away.
Context Anchor
Seen in airplane systems descriptions, preflight checks, and discussions of the outer wing surfaces and tail section, especially where ice can collect on leading edges.
Derivation
From 'de-' meaning to remove or reverse, plus 'icing.' The 'de-' prefix signals that this equipment removes ice that is already there, which is the key distinction from anti-icing equipment that prevents ice from forming in the first place.
Why Pilots Care
Ice on wings and control surfaces reduces lift and can cause control problems or stalls; functioning deicing equipment is required for safe flight in icing conditions.
Analogy
Like turning on the defroster in a car to clear frost from the windshield before driving.
Intuition Check
Deicing does not mean preventing ice before it forms. Deicing removes ice that is already there; anti-icing means keeping ice from forming in the first place.
Example Sentence 1
Before takeoff in freezing rain, the crew requested deicing equipment to spray the wings and remove the layer of ice that had formed overnight.
Example Sentence 2
During the preflight inspection the instructor pointed out the deicing equipment boots along the leading edges of the wings.