What is the primary role of a magneto in an ignition system?

The primary role of a magneto in an ignition system is to generate high-voltage electrical current for ignition. In aviation, especially with reciprocating engines, the magneto is a crucial component that produces the electricity needed to ignite the fuel-air mixture in the engine's cylinders.

When the engine is cranked, the magneto uses the principles of electromagnetic induction. As the rotor spins inside a magnetic field, it generates a high-voltage electrical current that flows to the spark plugs. This high voltage is necessary to jump the gap of the spark plug electrodes, allowing for the ignition of the mixture and ultimately powering the engine.

This self-contained system, which operates independently of the aircraft's battery, provides reliability, ensuring that the engine can start and run even if electrical failure occurs elsewhere in the aircraft's systems. In this way, the magneto is critical for maintaining the engine's operation.

Other roles in the options, such as regulating fuel flow, controlling engine speed, or monitoring engine performance, are performed by different components within the aircraft's engine systems and are not related to the fundamental purpose of the magneto.