Published date: 27 April 2007


This Advisory Circular (AC) describes an acceptable means of compliance with Part 21 Subpart Q. Each reference to a number in this AC, such as 21.15, is a reference to a specific rule within Part 21.


This material is intended for a product manufacturing organisation, or a person performing maintenance, in completing or replacing product identification markings.

Related rules

This AC relates specifically to Part 21 Subpart Q Identification of Products and Parts.

Change notice

Revision 2 re-numbers this AC from AC21-80A to AC21-6 as part of a project to standardise the numbering of all ACs.