Airworthiness Directive (AD)

An Airworthiness Directive is a legally enforceable instruction from a regulator (e.g. the FAA or EASA) requiring inspection, repair or modification to correct an unsafe condition found on an aircraft, engine or component type. Compliance is mandatory; an aircraft's AD status is a key part of pre-purchase diligence and its records.

Why it matters: an AD is regulatory law applied to a specific aircraft, engine or component — a mandatory correction of an unsafe condition, with a defined compliance deadline or interval. Operating with an overdue AD renders the aircraft unairworthy regardless of its physical condition.

For buyers, AD status is a direct pricing input: outstanding directives, and any that are recurring, transfer their cost and downtime to the new owner the day the deal closes. A complete AD compliance record is part of what a pre-purchase records review must establish — and gaps here are non-negotiable findings.