Private Pilot Private Exam

If the ignition switch ground wire gets disconnected, what may happen to the magneto?

1. It will stop firing completely

2. It may continue to fire

3. It will only fire intermittently

4. It will increase firing rate

The correct answer is: It may continue to fire

When the ignition switch ground wire becomes disconnected, the magneto may continue to fire. This is because the magneto is designed to generate its own electrical power independently of the battery. Its operation relies on mechanical motion and the magnetic field, and the grounding of the ignition switch is primarily a safety feature to stop the magneto from producing a spark when the engine is not running. If the ground wire is disconnected, the magneto will not receive the signal to cease operation. As long as the engine is turning and the magneto is spinning, it can still generate sparks at the spark plugs. This scenario underscores the magneto's reliability and self-sufficient design, making it capable of functioning even if a ground connection is compromised. Therefore, it can continue to fire, which is critical for ensuring that the engine can run smoothly under various circumstances.