What is true regarding propellers and the Airworthiness Directive system?

The correct answer emphasizes that propellers are not included in the Airworthiness Directive (AD) system in the same way that other aviation components may be. The Airworthiness Directive system is primarily concerned with ensuring that all components of an aircraft meet safety standards and address any issues that could jeopardize airworthiness.

However, propellers, while crucial to aircraft operation, can sometimes fall under different regulatory frameworks depending on their design and usage. They may be managed through specific manufacturer guidelines or service bulletins rather than the broader AD system. This distinction helps ensure that each component is regulated appropriately, considering its unique characteristics and operational contexts.

By understanding that propellers are treated differently in regulatory terms, one can appreciate the complexities involved in aircraft maintenance and the importance of following the relevant guidelines for each component to maintain safety and compliance.