Airworthiness Directives: Overview
Airworthiness Directives (ADs) are a set of legally enforceable rules that apply to aircraft and the following aircraft products: engines, propellers, and equipment, such as; parachutes, seat belts, and fire extinguishers.
They are mandatory instructions, issued by the Minister of Transport or a foreign airworthiness authority, that amend an approval document relating to an aeronautical product which may require modification, replacement or special inspection to ensure that it complies with approved design data and is in a condition for safe operation.
They are documents issued or adopted by the Civil Aviation Authority of the State of Registry of a given aircraft. For example, TC will adopt all FAA AD’s issued against Boeing products as the USA is the type certificate holder (TCH) for Boeing, and the Canadian aircraft register contains Boeing products.
An AD mandates actions to be performed to restore an acceptable level of safety to an aircraft, when evidence shows that the safety level may otherwise be compromised.
Canadian ADs are issued by the Minister pursuant to the conditions prescribed in Canadian Aviation Regulation, Part V, Subpart 93 (CAR 593). Pursuant to CAR Part VI, Subpart 5, section 84 (CAR 605.84) and the further details of CAR Standards (Airworthiness Manual) 593 and 625, the continuing airworthiness of a Canadian aircraft is contingent upon compliance with all applicable ADs. Failure to comply with the requirements of an AD causes the certificate of airworthiness of the aircraft to be out of force. Applications for an alternative means of compliance with the requirements of an AD must be made in accordance with CAR Standard 625, Appendix H.
An Airworthiness Directive contains, at a minimum, the following information:
Identification of an unsafe condition.
Identification of the affected aircraft by manufacturer/model association.
Actions required to restore the aircraft to an acceptable level of safety.
Compliance time for the required action(s).
Effective date.
An Airworthiness Directive is issued in the following cases:
An unsafe condition has been determined to exist in an aircraft because of a deficiency in the aircraft, or an engine, propeller, part, or appliance installed on this aircraft.
The condition is likely to exist or develop in other aircraft of similar type.
Application and responsibilities of an Airworthiness Directive are as follows:
The ADs applicable to an aircraft are those issued or adopted by the State of Registry of this aircraft.
No person may operate an aircraft to which an AD applies, except in accordance with the requirements of that AD, unless otherwise agreed with the Civil Aviation Authority of the State of Registry.
Distribution:
Upon issue, Transport Canada ADs are distributed to the registered owners of affected Canadian aircraft.
In accordance with ICAO Circular 95-AN/78 Transport Canada ADs are also distributed to the airworthiness authorities of foreign states (in the SIGS module) where Canadian certified products are believed to be operating.
There are other optional entities in the Special Interest Groups module (SIGS) to which ADs are forwarded, depending upon the circumstances
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