FAA Powerplant Written Practice Test

How does the clutch in a pneumatic starter function?

1. Remains engaged continuously

2. Is manually operated

3. Automatically engaged and disengaged

4. Only engages during maintenance

The correct answer is: Automatically engaged and disengaged

The function of the clutch in a pneumatic starter is designed to automatically engage and disengage based on operational needs. The pneumatic starter uses compressed air to spin the engine's components and initiate the engine start sequence. Once the engine reaches a certain speed, the clutch disengages to prevent the starter from overpowering the engine. This automatic engagement and disengagement mechanism ensures that the starter operates efficiently without causing unnecessary wear or damage to the engine or starter components. By engaging only during the starting process and disengaging afterward, the clutch allows for a smooth transition from starter operation to the engine running independently, which is critical for both performance and safety. This design is integral to the efficiency of pneumatic starters in aviation applications.