FAA Powerplant Written Practice Test

When the centrifugal force acting on the propeller governor flyweights overcomes the tension on the speeder spring, the propeller is in what condition?

1. Normal operating speed

2. Under-speed

3. Over-speed

4. Critical pitch

The correct answer is: Over-speed

When the centrifugal force acting on the propeller governor flyweights exceeds the tension on the speeder spring, the propeller enters an over-speed condition. This occurs because the governor system is designed to maintain a specific propeller speed by adjusting the blade pitch. As the centrifugal force increases with engine power, it pulls the flyweights outward. If this force surpasses the opposing force from the speeder spring, the governor will move to increase the blade pitch, leading to a higher engine RPM than desired. In an over-speed condition, the engine may run beyond its optimal or safe RPM range, potentially resulting in mechanical failure, excessive vibration, or other dangerous operational issues. Therefore, understanding the balance between centrifugal force and speeder spring tension is crucial for maintaining proper propeller operation and safety.