FAA Aircraft Dispatcher Practice Exam

What is the primary source of heat for engine and wing anti-ice systems?

1. Electrical heating elements

2. Hot air from the engine

3. Chemical heaters

4. Radiant heat from the sun

The correct answer is: Hot air from the engine

The primary source of heat for engine and wing anti-ice systems is hot air from the engine. This is achieved through a process known as bleed air, where compressed air is taken from the engine's compressor stage. This hot air is then ducted to various parts of the aircraft, specifically the wings and engine inlets, to prevent ice accumulation in critical areas during flight. Using bleed air is efficient and effective because the engines are already generating this heat as part of the combustion process. This method is commonly utilized in many aircraft because it can provide continuous heating as long as the engines are operational. The design ensures that crucial surfaces remain ice-free, maintaining aerodynamic efficiency and safety during flight under icy conditions. This contrasts with other options: while electrical heating elements and chemical heaters can be used in some systems, they are not the primary sources for most traditional aircraft anti-ice systems. Radiant heat from the sun is not a reliable source for de-icing, given that it depends on daylight conditions and can’t be counted on during flight in overcast or stormy weather.