Definition
A system that prevents ice from forming on critical aircraft surfaces — typically engine inlets, cowlings, and wing leading edges — by heating those surfaces with hot air bled from the engine compressor. Because the surface is kept warm, supercooled water droplets striking it cannot freeze and accumulate.
Plain English
A way of stopping ice from forming on the aircraft by piping hot engine air into the parts most likely to ice up, keeping them warm enough that water can't freeze on them.
Context Anchor
Seen in turbine aircraft engine controls, maintenance procedures, and discussions of ice protection in freezing moisture.
Derivation
Thermal comes from the Greek thermē, meaning heat. Anti-ice simply means 'against ice.' Together: using heat to keep ice from forming.
Why Pilots Care
Ice buildup can restrict airflow, reduce engine performance, or cause damage from ingested ice; the system maintains safe operation in cold, moist conditions.
Intuition Check
TAI is not mainly for breaking off a large amount of ice after it has already formed. Its normal purpose is to keep critical surfaces warm enough that ice does not build up in the first place.
Example Sentence 1
The crew turned on TAI before climbing through the cloud layer to keep the engine inlets free of ice.
Example Sentence 2
During the preflight inspection, the mechanic verified that the TAI valves opened when selected.