In aviation regulation, the term Airworthiness Directives refers to

• A. Directives Addressing Safety Issues and Mandatory Actions
• B. Advisory Notices About Preferred Routes
• C. Manufacturer Service Letters
• D. Local Airspace Rules

Answer: (A)

Airworthiness Directives are mandatory directives issued by the aviation authority to correct unsafe conditions in aircraft. When an unsafe condition is identified, the regulator issues an AD that specifies which aircraft are affected, the required corrective actions (such as inspections, repairs, modifications, or parts replacements), and the time frame for compliance. Compliance is legally required for continued airworthiness, so not following an AD can render the aircraft not airworthy and subject to enforcement.

This concept is distinct from advisory notices about preferred routes, which are not mandatory directives; manufacturer service letters, which are guidance rather than enforceable requirements; and local airspace rules, which govern airspace use rather than airworthiness conditions.