ATPL - The heating facility for the windshield of an aircraft is:

Question id 307 - Aircraft General Knowledge - Airframe, Systems, Powerplant - ATPL - Airline Transport Pilot license

Used Only At Low Altitudes Where There Is A Risk Of Ice Formation.

Used on a continual basis as it reduces the thermal gradients which adversely affect the useful life of the components.

Only used when hot air demisting is insufficient.

Harmful To The Integrity Of The Windows In The Event Of A Bird Strike.