What category of aircraft is primarily affected by ADs as per regulation?

The regulation regarding Airworthiness Directives (ADs) applies to both experimental and standard aircraft categories. This means that all aircraft, regardless of their classification, must adhere to the directives issued by the Federal Aviation Administration (FAA) to ensure safety and compliance with current airworthiness standards.

Experimental aircraft, which are often used for testing or educational purposes, are subject to ADs to prevent potential safety hazards stemming from design flaws or component failures. Similarly, standard aircraft, which encompass most commercial and general aviation planes, are also required to comply with ADs as they contribute significantly to public safety.

This inclusive approach is crucial because it ensures that any safety issue identified in either category of aircraft is addressed promptly, thereby minimizing risks to pilots, passengers, and the flying public at large. Hence, the correct answer acknowledges the broad application of ADs across different types of aircraft.