Catalog of Aerospace Standard (AS) Parts

A component or material may be identified as a “standard part” when it meets certain criteria within various stages: including design, manufacturing, test and acceptance, and uniform identification. Some items such as certain electronics, may qualify as a standard part if they have met specific performance criteria. The term aerospace standards is not defined in Title 14 of the CFRs. However, the FAA has issued a non-regulatory definition of this designation and accepts proper identification of AS parts.

The criteria may be listed by established industry specifications or by U.S. Government- published specifications. For example, an aerospace parts manufacturers should specify how the part should be made and with what material; all specifications must be met by all PMA holders.

Although this standard is not federally regulated, there are processes in place that ensure that parts are being made according to their specifications. The FAA may oversee any manufacturer or supplier of standard parts when they are going to be installed. Standard part manufacturers may also be subject to audits by customers; and findings must conclude that all criteria are being met.

There are several different categories of Aerospace Standards:

• National Aerospace Standard (NAS)
• Army-Navy Aeronautical Standard (AN)
• Society of Automotive Engineers (SAE)
• Joint Electronic Device Engineering Council
• Joint Electron Tube Engineering Counsel
• American National Standards Institute (ANSI)

Many hardware components receive a standard part designation: nuts, bolts, etc. However, it is not feasible for every single part to have this designation; there are billions of small parts used in aerospace applications and some designs are unique. To ensure that safety standards are being met, the FAA issued special orders for certain components. The FAA issues Technical Standard Orders (TSOs) to ensure that specialized fasteners, seals, and bearings meet minimum performance, marking, and installation approval requirements. These include TSO-C148 (Aircraft Fasteners), TSO-C149 (Aircraft Bearings), and TSO-C150 (Aircraft Seals). This system increases safety in the aerospace industry because not all parts are required to have published specifications.

Standard parts should come with their Certificate of Compliance (CoC), a marking that indicates that it has been made in compliance with specifications and should have traceability. Maintenance, preventive maintenance, rebuilding, and alteration regulations are listed under Title 14, Part 43, of the CFRs. Personnel must fully adhere to all FARs when installing a standard part or replacing them with identical standard parts.