View source for Ice protection system

=== Pneumatic deicing boots ===
[[file:Deicing boots on the leading edge of the wing.png|thumb|When ice builds up on the leading edge, an engine-driven pneumatic pump inflates the rubber boots. <ref>Left blank intentionally</ref>]]
The [[Deicing boot|pneumatic boot]] is usually made of layers of [[Synthetic rubber|rubber]] or other [[elastomer]]s, with one or more air chambers between the layers. If multiple chambers are used, they are typically shaped as stripes aligned with the long direction of the boot. It is typically placed on the leading edge of an aircraft's wings and stabilizers. The chambers are rapidly inflated and deflated, either simultaneously, or in a pattern of specific chambers only. The rapid change in shape of the boot is designed to break the adhesive force between the ice and the rubber, and allow the ice to be carried away by the air flowing past the wing. However, the ice must fall away cleanly from the trailing sections of the surface, or it could re-freeze behind the protected area. Re-freezing of ice in this manner was a contributing factor to the crash of [[American Eagle Flight 4184]].

Older pneumatic boots were thought to be subject to ice bridging. Slush could be pushed out of reach of the inflatable sections of the boot before hardening. This was resolved by speeding up the inflation/deflation cycle, and by alternating the timing of adjacent cells.<ref>{{cite web|url=https://www.nbaa.org/ops/safety/in-flight-safety/icing/deicing-boots-training-20090421.pdf|title=FAA Information for Operators 09005}}</ref> Testing and case studies performed in the 1990s have demonstrated that ice bridging is not a significant concern with modern boot designs.{{sfn|Federal Aviation Administration|2015|p=20}}

Pneumatic boots are appropriate for low and medium speed aircraft, without leading edge lift devices such as [[Slat (aircraft)|slats]], so this system is most commonly found on smaller [[turboprop]] aircraft such as the [[Saab 340]] and [[Embraer EMB 120 Brasilia]]. Pneumatic de-icing boots are sometimes found on other types, especially older aircraft. These are rarely used on modern jet aircraft. They were invented by [[Goodrich Corporation|B.F. Goodrich]] in 1923.