FAA Powerplant Written Practice Test

In automatic starting systems on small reciprocating engine aircraft, what is energized to allow current to flow to the starter motor?

1. Starter relay

2. Starter switch

3. Starter solenoid

4. Starter capacitor

The correct answer is: Starter solenoid

In automatic starting systems on small reciprocating engine aircraft, the component that is energized to allow current to flow to the starter motor is the starter solenoid. The starter solenoid functions as a high-current relay, bridging the low-power control circuit from the starter switch to the high-power circuit that drives the starter motor. When the starter switch is engaged, it sends a signal to the solenoid, which then closes the circuit and allows the necessary current to flow to the starter motor. This action initiates the starting process of the engine by providing the required electrical energy to turn the motor. Understanding this function highlights the importance of the starter solenoid in the overall starting system, differentiating it from other components such as the starter relay, starter switch, or starter capacitor, which perform different roles in the system.