Plain English Meaning

A small generator on the engine that makes its own electricity to create the sparks that ignite the fuel. It works on its own, without needing the airplane's battery, so the engine keeps running even if the electrical system fails.

Full Definition

An engine-driven electrical generator that produces high-voltage current to fire the spark plugs in a piston aircraft engine, using a rotating magnet and coil rather than the airplane's battery or electrical system. Most certified piston aircraft have two independent magnetos (left and right) for redundancy, each firing one of the two spark plugs in every .