FAA Powerplant Written Practice Test

How is an out-of-balance propeller typically corrected?

1. By adjusting the control rods

2. By adding weight on the light side

3. By removing material from the heavy side

4. By using an electronic balancing system

The correct answer is: By adding weight on the light side

An out-of-balance propeller is typically corrected by adding weight to the light side. This method addresses the imbalance directly by compensating for the weight discrepancy that causes the vibrations and other issues associated with an unbalanced propeller. When a propeller is out of balance, it causes excess vibration, which can lead to excessive wear on the engine and airframe components. Adding weight to the lighter side of the propeller redistributes the mass, thereby helping to achieve a more uniform rotational motion. Other methods like adjusting control rods or using an electronic balancing system can assist in other types of adjustments or balances in different systems but are not the primary means of correcting propeller balance. Additionally, while removing material from the heavy side might be considered in certain scenarios, it is generally more complex and not the first line of action for propeller balancing compared to adding weight.