Definition
Aircraft systems designed to prevent or remove ice accumulation on critical surfaces such as wings, tail, propellers, windshields, pitot tubes, and engine inlets. Anti-icing systems prevent ice from forming in the first place; de-icing systems remove ice after it has begun to accumulate.
Plain English
Equipment fitted to an aircraft that either stops ice from forming or breaks ice off once it has formed, keeping the aircraft flyable in icing conditions.
Context Anchor
You will see this term in icing discussions, aircraft equipment lists, checklists, and procedures for leaving unexpected icing conditions.
Derivation
Anti- comes from the Greek for 'against' (preventing ice), and de- comes from Latin for 'remove' (taking ice off). The two prefixes signal the two different jobs: stopping ice forming versus removing ice already there.
Why Pilots Care
Ice on wings or control surfaces reduces lift and increases drag, so this equipment is essential for safe flight in cold conditions.
Analogy
It is like the difference between spraying a windshield so ice is less likely to stick and using a scraper after ice is already there. One helps prevent the problem; the other helps remove it.
Grounding Statement
In an icing encounter, this equipment is meant to protect the aircraft long enough for the pilot to follow the proper procedure, usually including leaving the icing conditions.
Intuition Check
Do not assume “anti-icing/de-icing equipment” means the aircraft is approved or safe for all icing. It only means the aircraft has specific equipment for preventing or removing ice, with limits set by that aircraft’s design and operating instructions.
Example Sentence 1
Before departing into forecast icing conditions, the pilot confirmed that all anti-icing/de-icing equipment was operational.
Example Sentence 2
During the preflight inspection the crew verified that the anti-icing/de-icing equipment was fully operational.