Final answer:
The most common type of alternator in aircraft AC systems is the brushless alternator, due to its reliability and maintenance advantages over brushed systems. It is essential for running systems like the Thermawing and Thermacool on aircraft.
Step-by-step explanation:
The most common type of alternator used in most aircraft AC systems is the brushless alternator. Aircraft typically require reliable and efficient systems to power various functions such as the Thermawing anti-icing/deicing system and the Thermacool air conditioning setup. While automotive applications often use a lead-acid battery for their high-current demands, aircraft necessitate a more continuous and consistent power supply that is optimally provided by brushless alternators. These alternators are preferred because of their high reliability and low maintenance requirements due to the absence of brushes which can wear out over time and require replacement. They have high output capability, necessary to run energy-intensive systems like the Thermawing, which is an essential feature for pilot safety in icing conditions, and Thermacool, which can be operated before the engine starts.