What is the function of magnetos?

• A. To provide current to your spark plugs
• B. To regulate battery charging
• C. To power avionics
• D. To control fuel flow

Answer: (A)

Magnetos are self-contained ignition sources that generate and deliver the spark needed to ignite the fuel-air mixture in each cylinder. They’re engine-driven and independent of the aircraft’s battery or electrical system, so the engine can continue to ignite even if the battery or alternator isn’t supplying power. Inside a magneto, a rotating magnet and coil create a high-voltage spark, which is routed to the spark plugs in the correct sequence and timing through a distributor and ignition leads. Many aircraft have two magnetos to provide redundancy, so if one circuit fails the other can still operate the engine.

This is why the function is to provide current to the spark plugs. It isn’t responsible for regulating battery charging, powering avionics, or controlling fuel flow, which are handled by the charging system, electrical bus, and fuel metering system, respectively.