An Airworthiness Directive (AD) is a regulatory requirement issued by the Federal Aviation Administration (FAA) that mandates specific actions to be taken by aircraft owners, operators, and maintenance personnel to ensure the continued airworthiness of an aircraft.

The purpose of an AD is to:

1. Correct a known safety problem: Identify and address a specific safety concern or defect that could potentially lead to an accident or incident.
2. Prevent future problems: Take proactive measures to prevent a potential safety issue from arising.
3. Maintain airworthiness: Ensure that the aircraft remains airworthy and compliant with regulatory requirements.

ADs typically apply to specific aircraft models, engines, or components, and may require actions such as:

• Inspections or tests
• Repairs or replacements of parts
• Modifications or upgrades
• Changes to operating procedures or maintenance schedules

Non-compliance with an AD can lead to:

• Grounding of the aircraft
• Loss of airworthiness certification
• Fines and penalties
• Increased risk of accidents or incidents

FAA ADs are usually issued in response to:

• Service difficulty reports (e.g., pilot or mechanic reports of issues)
• Accident or incident investigations
• Manufacturer notifications (e.g., service bulletins or alerts)
• Regulatory changes or updates

There are different types of ADs, including:

• Mandatory ADs: Require immediate action to ensure safety.
• Optional ADs: Recommend actions but do not require them.
• Proposed ADs: Published for public comment before becoming final.

Aircraft owners, operators, and maintenance personnel must comply with applicable ADs to ensure the safety of the aircraft, its occupants, and the general public.