What is the difference between deice and anti-ice?

Question

Most aircraft contain systems which are used to mitigate problems which could be caused by ice. This includes everything from a heated pitot tube to a wing leading edge heated by bleed air. These systems are usually referred to as either deice or anti-ice systems.

score 8 · Accepted Answer · answered Sep 01 '15 at 02:11

8

De-ice is a system that removes ice that has formed on a part.

Anti-ice is a system that prevents ice from forming on a part.

A heated leading edge(bleed air) is an example of an anti-ice system.

A inflatable boot on a leading edge is an example of a de-ice system.

answered Sep 01 '15 at 02:11

Steve H

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Does this mean that if ice has already formed that anti-ice is generally ineffective? – ryan1618 Sep 01 '15 at 02:35
Certain systems can do both I think. e.g. for the chemical fluids sprayed on the wings there's a different dose / composition I recall for the de-ice application versus an anti-ice application. – curious_cat Sep 01 '15 at 06:15
@curious_cat ground deice uses one of several types of fluid which are usually applied hot (to deice) and have a specified "holdover time" (for how long the fluid remaining on the wing provides anti-ice protection). That's a different situation than in-flight de-ice/anti-ice though. – voretaq7 Sep 01 '15 at 17:57
@voretaq7 Thanks! That's a tricky situation sometimes. I recall reading incident reports where a de-ice application was requested but an anti-ice application was made (or maybe vice versa) and things can get dangerous later if it goes undetected. – curious_cat Sep 01 '15 at 19:14

score 5 · Answer 2 · answered Sep 01 '15 at 03:16

As the name indicates, anti-icing systems prevent the formation of ice (aircraft surfaces) while the de-icing systems remove the ice after it is formed.

Anti-icing systems can be active or passive. In general, most of the active anti-icing systems are thermal, which use the engine bleed air routed through the pipes in wings, engine intakes etc.

Source: navyaviation.tpub.com

Another method of anti-icing is to have resistive circuits in wings, which can be generate heat when current is passed, preventing ice formation. This can be used also in de-icing mode to remove ice, which is more energy efficient compared to the anti-icing mode.

One of the oldest de-icing method was the pneumatic one, which uses an inflatable rubber boot to remove accumulated ice from leading edges of wings.

"Deicer (PSF)" by Pearson Scott Foresman - Archives of Pearson Scott Foresman, donated to the Wikimedia Foundation→This file has been extracted from another file: PSF D-240001.png.. Licensed under Public Domain via Commons.

What is the difference between deice and anti-ice?

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