Definition
A type of ice protection system in which electrical heating elements embedded in panels or 'boots' on the leading edges of wings, tail surfaces, or propellers warm the surface enough to break the bond between accumulated ice and the airframe, allowing aerodynamic forces or centrifugal force to shed the ice.
Plain English
Heating pads built into the leading edges of the wings, tail, or propeller that warm up using electricity to melt the grip of any ice that has formed, so the ice falls off.
Context Anchor
Seen in anti-icing and deicing system descriptions, aircraft checklists, and operating manuals for airplanes equipped to handle icing conditions.
Derivation
Electrothermal' combines 'electro-' (electricity) and 'thermal' (heat) — heat produced by electricity. 'Boots' is borrowed from the older pneumatic deicing boots, the rubber covers fitted over leading edges. The name was kept because the panels look and sit in the same place, even though the working method is completely different.
Why Pilots Care
Ice accumulation reduces lift, increases drag, and raises stall speed; these boots restore normal flight characteristics by removing the ice.
Intuition Check
“Boots” does not mean footwear here. In this context, a boot is a protective covering fitted to part of the aircraft, and “electrothermal” means it is heated by electricity.
Example Sentence 1
After entering icing conditions, the crew activated the electrothermal boots and watched the wing leading edges shed ice in cycles.
Example Sentence 2
During the preflight check the pilot confirmed the electrothermal boots heated evenly across both wings.