ATPL Airframe Practice Test 2025 – Comprehensive All-in-One Guide to Exam Success!

The main source of the thermal anti-icing system in jet airplanes is bleed air from the engines. This system works by using compressed air that is extracted from the engines, which is then hot enough to effectively prevent the formation of ice on critical surfaces of the aircraft, such as leading edges of wings and tail surfaces. The use of bleed air for this purpose is efficient because the engines are already producing this air as part of their operation, and it can be directed to areas where ice typically forms without requiring additional equipment or systems.

This method is particularly advantageous in flight, where maintaining aerodynamic surfaces free of ice accumulation is crucial for performance and safety. Any alternative choices, such as using turbo compressors, ram air heated through a heat exchanger, or the Auxiliary Power Unit (APU), do not provide the same level of efficiency or effectiveness for thermal anti-icing as using engine bleed air, which is readily available and specifically designed for these operational needs.