FAA Powerplant Written Practice Test

In case of engine failure, what holds a feathered propeller in position while in flight?

1. Hydraulic pressure

2. Mechanical latches

3. Aerodynamic force

4. Magnetic locks

The correct answer is: Aerodynamic force

A feathered propeller is designed to minimize drag in the event of an engine failure, and it achieves this by aligning the blades parallel to the airflow. The correct answer, aerodynamic force, plays a crucial role in maintaining this position while in flight. When a propeller is feathered, the angle of the blades is changed such that the lift produced by the blades actually counters the weight of the propeller, effectively holding it in the feathered position without requiring any additional active mechanisms. This aerodynamic stability allows the propeller to remain in its feathered position until positive input is given by the pilot to adjust the blades back to a non-feathered position, such as during an engine restart or if the pilot chooses to land. This ensures that drag is minimized and that the aircraft can glide more efficiently in an emergency situation. The other options provided do not accurately describe the mechanism that holds a feathered propeller in place. For instance, hydraulic pressure may be involved in the initial feathering mechanism but does not hold it in position during flight. Similarly, mechanical latches and magnetic locks are not typically used in the design of feathering mechanisms for propellers. Understanding the role of aerodynamic forces is essential for recognizing how feathered propellers contribute to flight