Definition
A legally enforceable regulatory notice issued by the FAA to correct an unsafe condition found to exist in an aircraft, engine, propeller, or appliance. ADs identify the affected products, describe the unsafe condition, and prescribe the inspections, modifications, or operating limitations required to address it. Compliance is mandatory for the aircraft to remain airworthy.
Plain English
An official FAA order that says: 'A safety problem has been found on this type of aircraft or part. Here's what you must do, and by when, to keep flying it legally.'
Context Anchor
Seen in NOTAM information when a notice applies broadly to an airport or landing area.
Derivation
From 'airworthy' (fit and safe to fly) plus 'directive' (an authoritative instruction). Together: an order that must be followed to keep the aircraft fit to fly.
Why Pilots Care
Pilots check AD information to understand runway, taxiway, or facility conditions that affect flight planning and safety.
Intuition Check
Do not read AD here as Airworthiness Directive. In this NOTAM context, AD means aerodrome: the airport or landing area.
Example Sentence 1
Before flying the rental Cessna, the pilot checked the maintenance logs to confirm all ADs had been complied with.
Example Sentence 2
Review the AD section of the NOTAM before departure to confirm runway status.