What component is primarily responsible for the ignition of fuel in an aircraft engine?

The primary component responsible for the ignition of fuel in an aircraft engine is the magneto. The magneto generates high voltage electricity necessary to create the spark needed for igniting the air-fuel mixture in the engine's cylinders. It does this by converting mechanical energy from the engine's rotation into electrical energy. The spark plug then uses this high voltage to produce a spark, which ignites the fuel in the combustion chamber, allowing the engine to function.

In aviation engines, particularly in piston engines, the reliability of magnetos is crucial since they operate independently of the aircraft's electrical system. This independence ensures that the engine can continue to operate even if there’s a failure in the electrical system, providing an essential safety feature.

While the fuel injector is vital for delivering the right amount of fuel into the engine, it is not responsible for ignition itself. Similarly, the ignition coil plays a role in some ignition systems by supplying voltage to the spark plugs, but it is not the primary component in an aircraft engine setting. The starter motor is responsible for cranking the engine to initiate the ignition process but does not contribute to the actual ignition of the fuel once engine operation has begun.