What regulatory notice informs the registered owner of a condition that prevents continued airworthiness and requires compliance within a time limit?

• A. Airworthiness
• B. Airworthiness Certificate
• C. Airworthiness Directive
• D. Alternate static source

Answer: (C)

An Airworthiness Directive is the regulatory notice issued when a known unsafe condition exists in an aircraft, engine, propeller, or related part. It informs the registered owner or operator that the condition prevents continued airworthiness and requires corrective action within a specified time. Compliance with the directive is mandatory to maintain legal operation, and failing to follow it can render the aircraft unairworthy and subject to enforcement. This differs from an Airworthiness Certificate, which shows the aircraft met airworthiness requirements when issued, and from an alternate static source, which is a different aircraft system issue.