Airworthiness Directive

An Airworthiness Directive (commonly abbreviated as AD) is a notification to aircraft owner and operator of a known safety deficiency with a particular model of aircraft, engine, avionics or other system.

ADs usually result from service difficulty reporting by operators or from the results of aircraft accident investigations. They are issued either by the national civil aviation authority of the country of aircraft manufacture or of aircraft registration. When ADs are issued by the country of registration they are almost always coordinated with the civil aviation authority of the country of manufacture to ensure that conflicting ADs are not issued.

ADs are issued by most civil aviation regulatory authorities, including:

*Civil Aviation Safety Authority (Australia)
*European Aviation Safety Agency
*Federal Aviation Administration (USA)
*Transport Canada
*Joint Aviation Authorities (Europe)

ADs are mandatory in most jurisdictions and often contain dates or aircraft flying hours by which compliance must be completed. Some ADs are of such a high priority that compliance must be completed prior to the next flight of the aircraft.

External links

* [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet FAA Airworthiness Directives]
* [http://ad.easa.europa.eu/ EASA Airworthiness Directives]
* [http://www.tc.gc.ca/aviation/applications/cawis-swimn/awd-lv-cs1401.asp?rand= Continuing Airworthiness Web Information System (CAWIS) - Provided by Transport Canada]