Question id 363 - Aircraft General Knowledge - Airframe, Systems, Powerplant - ATPL - Airline Transport Pilot license

Only used when hot-air defogging is insufficient.
Essential to improve the strength of the cockpit windows.
Used only at low altitudes where there is a risk of ice formation.
Not affecting the strength of a cockpit windows.

Training tests and timed exam simulations ATPL - Airline Transport Pilot license