AD
Airworthiness Directive
A legally binding FAA notice requiring inspection, repair, or modification to maintain airworthiness.
An Airworthiness Directive is issued by the FAA when an unsafe condition exists in an aircraft, engine, propeller, or appliance. ADs are mandatory — compliance is required for the aircraft to be airworthy.
ADs come in two main forms: one-time (do once, sign off, done) and recurring (do every N hours or N calendar months). Some have a specific compliance window; emergency ADs may require compliance before next flight.
The owner is responsible for AD compliance, even if the work is performed by a mechanic. Maintenance logs must show every applicable AD and how it was complied with. At every annual, the IA reviews AD compliance as part of the airworthiness determination.
When it matters
Hours-based recurring ADs need to track against current Hobbs, not just calendar. The 100-hour spread can put you out of compliance without anyone noticing if tracking is manual.
In Aloft360
Track inspection due-dates