AMOC – Alternative Methods of Compliance is a different way, other than the one specified in an Airworthiness Directive (AD), to address the unsafe condition on an aircraft, aircraft engine, propeller or appliance. An AMOC must ensure the unsafe condition is corrected by providing an acceptable level of safety. An Airworthiness Directive (AD) contains the required method for correcting an unsafe condition.
An AMOC is required if an owner/operator cannot or does not wish to comply with the actions specified in an AD
Why an AMOC may be necessary or desirable include, but is not limited to the following:
- To accomplish AD actions in a way that better suits an owner/operator’s business processes.
- An owner/operator devises another or better way of addressing the unsafe condition.
- An owner/operator wishes to adjust the compliance time to an AD.
- Because existing modifications, alterations, or repairs to a product make compliance with AD procedures difficult or impossible.
- To use later revisions of service documents specified in an AD, or
- A superseding AD invalidates previous AMOCs to the original AD.
Different approaches or techniques that are not specified in an AD can, after FAA approval, be used to correct an unsafe condition on an aircraft or aircraft product. Although the alternative may not have been known at the time the AD was issued, an alternative method could be acceptable to accomplish the intent of the AD. 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 that is at least equivalent to that of the requirements of the AD.
Why have provisions for approval of an AMOC in an AD?
Provisions for an alternative method are desirable from an aircraft operator’s point of view and also eliminate the need for constant AD revisions when acceptable methods are developed for AD compliance. 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 different compliance times, for the requirements of the specific AD. One of the FAA Aircraft Certification Offices will have responsibility for AMOC approvals for a product manufactured in the United States. For a product manufactured outside the United States, a Standards Staff branch office of one of the four FAA Aircraft Certification Directorates will generally be listed in the AD as having responsibility for AMOC approvals.
EASA can accept AMOC applications for any AD that has been issued or adopted by EASA, i.e:
- ADs that EASA has issued and published online in its AD Tool
- ADs that EASA has approved and published in its AD Tool (i.e. an AD previously published in the period 2003-2006 by the EU MS NAAs)
- ADs that EASA has grandfathered, as per Regulation (EC) No 1702/2003, and,
- ADs that EASA has adopted i.e. Foreign State of Design ADs on non-EU products.