Airworthiness Directive (AD)
What is an Alternative Method of Compliance (AMOC) for an Airworthiness Directive (AD)?
An AD contains the required method for resolving an unsafe condition in an aircraft, aircraft engine, propeller, or appliance. An AMOC provides an acceptable level of safety for a different way, other than the one specified in the AD, to address the unsafe condition. A compliance time that differs from the requirements of the AD can also be approved if the revised time period provides an acceptable level of safety.
Why have provisions for approval of an AMOC in an AD?
An AD provides one means to resolve the unsafe condition. There may be other ways that can be developed that also provide an acceptable level of safety. Additionally, an owner/operator may not be able to comply with the AD as written because of changes that have been made to their particular product. Those changes do not eliminate the need to comply with the AD, but may affect the method by which they comply. Without the ability to approve an AMOC, the owner/operator would either have to comply with the AD as written, which may be impossible, or ground the aircraft. AMOCs also provide owners/operators the ability to accomplish AD actions in a manner that better suits their business processes. If an AD does not contain provisions for approving an AMOC, the AD must be revised before compliance can be accomplished by any method other than what is stated in the AD.
Who has the authority to approve an AMOC?
Each AD will state which office within the FAA Aircraft Certification Service is responsible for that AD. The manager of the responsible office has the authority to approve an AMOC, including changes to compliance times, for the requirements of the specific AD. An office within the Compliance and Airworthiness Division will have responsibility for AMOC approvals. In some cases, the responsible office may delegate certain AMOC approval authority to type certificate holder designated engineering representatives (DERs) or organization designation authorization (ODA) holders. The AD will state if AMOC approval authority has been delegated.