What methods are used to supply heated air for thermal anti-icing systems?

The correct answer is that all of the methods listed can be employed to supply heated air for thermal anti-icing systems.

Using bleed air from the turbine engine compressor is a common method because it allows for the utilization of already heated air that is pressurized as part of the engine's operation. This air is routed to various components, ensuring they stay above critical temperatures and preventing ice formation.

Engine exhaust heat exchangers are also effective for thermal anti-icing systems. These exchangers capture heat from the engine exhaust, transferring it to the air that will then be used for de-icing or anti-icing. This method ensures that efficient use is made of the heat produced during engine operation.

Finally, ram air heated by a combustion heater is another method. This involves using ambient air that is then heated through combustion before being distributed to the necessary systems to prevent ice accumulation.

By integrating all these methods, aircraft can maintain effective thermal anti-icing capabilities in various operational conditions. Each method brings a unique advantage, allowing for flexibility based on the aircraft type and specific operational requirements.