Airworthiness Directives are issued primarily to:

Airworthiness Directives (ADs) are critical regulatory tools issued by aviation authorities to ensure the safety and airworthiness of aircraft. The primary purpose of ADs is to address and correct unsafe conditions that might exist in an aircraft, engine, propeller, or appliance. When the FAA or other aviation regulatory bodies determine that a particular defect or condition poses a risk, they issue an AD to mandate the necessary actions that must be taken by aircraft owners and operators to mitigate those safety risks.

The issuance of an AD indicates that there is a known safety issue that requires immediate attention, rather than broader aspects like enhancing overall aircraft performance, updating maintenance procedures, or specifying design changes. While these aspects can be important in the context of aircraft operation and maintenance, the fundamental reason for the existence of ADs is to correct and eliminate unsafe conditions that could potentially lead to accidents or incidents in aviation. Thus, focusing on remedying unsafe conditions makes the selection correct.