Advisory Circulars are issued in a numbered subject system corresponding to the subject areas of the Code of Federal Regulations (CFRs) (Title 14, Chapter 1, FAA).

Defining Airworthiness: Two main factors determine if an aircraft is airworthy: The aircraft conforms to its type certificate and authorized modifications; and. The aircraft must be in condition for safe operation.

Advisory Circulars are sometimes first published as drafts, open to public comment. You can find these drafts by visiting: https://.faa.gov/aircraft/draft_docs/afs_ac/

(1) An Advisory Circular (AC) provides information and guidance by describing an acceptable means, but not the only means, of demonstrating compliance with the regulations and standards.

Advisory circular (AC) refers to a type of publication offered by the Federal Aviation Administration (FAA) to provide guidance for compliance with airworthiness regulations, pilot certification, operational standards, training standards, and any other rules within the 14 CFR Aeronautics and Space Title.

There are two different classifications of FAA airworthiness certificates: Standard Airworthiness Certificate, and Special Airworthiness Certificate.

Special Airworthiness Certificates are issued for aircraft that do not meet the high standards set for “standard” aircraft but may be safely operated under limitations established in the FAR and/or prescribed by the issuing FAA inspector.