Advisory circular (AC) refers to a type of publication offered by the Federal Aviation Administration (FAA) to "provide a single, uniform, agency-wide system … to deliver advisory (non-regulatory) material to the aviation community."[1] Advisory circulars are now harmonized with soft lawAcceptable Means of Compliance (AMC) publications of EASA, which are nearly identical in content. The FAA's Advisory Circular System is defined in FAA Order 1320.46D.[2]
By writing advisory circulars, the FAA can provide guidance for compliance with airworthiness regulations, pilot certifications, operational standards, training standards, and any other rules within the 14 CFR Aeronautics and Space title, aka 14 CRF or FARs. The FAA also uses advisory circulars to officially recognize "acceptable means, but not the only means," of accomplishing or showing compliance with airworthiness regulations.[3][4] Advisory circulars may also contain explanations, clarifications, best practices, or other information of use to the aviation community.[2][5]
^"Advisory Circular". CFI Notebook. Certified Flight Instructor's Notebook. Retrieved 2024-04-20. Advisory Circulars (ACs) provide a single, uniform, agency-wide system that the FAA uses to deliver advisory (non-regulatory) material to the aviation community
^David B. Walen FAA, Civil Aircraft System Safety and Electromagnetic Compatibility, November 16, 2010, p. 6. "Compliance with Regulations: FAA Guidance for compliance with airworthiness regulations published within Advisory Circulars (ACs) | Define acceptable, but not the only, means to comply with the airworthiness regulations | For example, AC 25.1309-1A describes acceptable means for showing compliance with 14 CFR 25.1309"
^Hartman v. United States (United States District Court for the Western District of Oklahoma Feb 8, 2013) ("10. ACs are “advisory” only. ACs provide guidance such as methods, procedures, and practices acceptable to the FAA for complying with regulations and grant requirements. ACs may also contain explanations of regulations, other guidance material, best practices, or information useful to the aviation community. They do not create or change a regulatory requirement. An AC may reflect or restate ways to implement regulatory requirements otherwise established by statute, regulation or grant agreements, but, by FAA order, an AC itself may not impose requirements or prohibitions. (Deemed admitted by the court for the reasons discussed below.)"), Text. Note: This is verbatim from FAA Order 1320.46D.