What is the primary purpose of the ignition system?

The primary purpose of the ignition system is to ignite the air and fuel mixture within the engine's combustion chamber. This process involves generating a spark at the right moment during the engine's cycle, which initiates combustion. When the air-fuel mixture is ignited, it creates the necessary pressure that drives the pistons, producing the power needed to operate the engine effectively.

While starting the engine is a resulting function of the ignition system, it encompasses the broader purpose of igniting the fuel-air mixture that is critical for engine operation. The other options, such as cooling the engine and monitoring temperature levels, relate to different systems within the aircraft that manage engine performance and safety but do not directly involve the ignition process.