“Standard parts” has come to be understood by the aviation and manufacturing public as meaning a part, the specification for which has been published by a standard-setting organization or by the U.S. Government, and the FAA has traditionally regulated parts production with that understanding.

Examples of such “traditional” standard part specifications include National Aerospace Standards (NAS), Air Force-Navy Aeronautical Standard (AN), Society of Automotive Engineers (SAE), SAE Aerospace Standard (AS), and Military Standard (MS). The FAA considers parts conforming to these standards as standard parts.

For a specification to be acceptable, it must include information on the design, materials, manufacture, and uniform identification requirements. The specification has to include all the information necessary to produce the part and ensure its conformity to the specification. Furthermore, the specification must be publicly available, so that any party is capable of manufacturing the part. The above examples of accepted specifications fulfill those criteria.