FAA Powerplant Written Practice Test

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

1. Constant speed

2. Feathered

3. Over-speed

4. Under-speed

The correct answer is: Over-speed

The propeller is in an over-speed condition when the centrifugal force acting on the flyweights of the propeller governor overcomes the tension on the speeder spring. In this scenario, the increased RPM causes the flyweights to move outward, which in turn raises the governor's signal to adjust the pitch of the propeller blades. When the centrifugal force surpasses the spring tension, it indicates that the propeller is rotating faster than its intended constant speed limit. This condition requires immediate attention because it can lead to excessive blade angles and possible structural damage to the propeller or the engine. In a proper functioning governor system, the governor would automatically adjust the pitch to manage this over-speed condition by increasing the blade angle, reducing the RPM back to a safe and stable operating range.