Parts is Parts!

Learning how to manage aircraft parts can make you more efficient and keep you out of hot water


The purchase, installation, and approval for return to service of the installed aircraft parts, combined with inspections, is the heart of the aircraft maintenance function. The regulations that govern replacement parts (short of FAR 43.10), have not changed appreciably since the conversion of all regulations from CAR to FAR as part of the Aviation Act of 1958.

FAR 43.10, “Disposition of life-limited aircraft parts,” was added as part of Amdt. 43-38, Eff. 4/15/2002 to clarify what a life-limited part is and provide some long needed instructions on how to handle them. In this article we will discuss parts and the handling of parts in detail, including life-limited parts.

What makes a usable part?

A usable part is one that has been through at least one FAA-approved quality assurance process and has successfully passed the inspection criteria of that process.

As a maintenance organization, certificated repair station, or individual, you are responsible for ensuring that all parts installed during maintenance meet the certification requirements of 14 CFR Part 21.303 “Replacement and modification parts.” Following are the five possible certification methods for NEW parts.

  1. PMA — Parts Manufacturing Approval applies only to specific part numbers and is usually associated with an STC or a direct replacement (non-OEM) part.
  2. PAH — Parts manufactured under the production certificate or the holder of the type certificate for that aircraft.
  3. TSO — Technical Standard Order applies to a specific FAA approved design. The organization manufacturing the TSO parts must hold TSO authorization from the FAA.
  4. Standard parts — Parts that are manufactured in accordance with an industry recognized standard such as AN, NAS, MS hardware and certain nonprogrammable electronic devices.
  5. Owner-produced parts — Parts produced by the aircraft owner (or his agent) for a specific purpose and for the repair of his aircraft. It is important to point out that owner produced parts are not exempt from FAA approval for complex fabrication.
    Although 14 CFR Part 21 addresses certification methods for new replacement parts, a certification method is also required for used parts. The certification of a used part is identified by its approval for return to service under 14 CFR Part 43 (Reference Part 43.13 and 43.9).

An approved vendor list

The first step is to develop a simple list of parts vendors that you have determined will send you approved parts when you order from them. Providing and enforcing such a list to your purchasing agent will ensure that only good parts are ordered in the first place, thus beginning the quality assurance process before the parts actually get to your doors.

Additionally, you should develop a procedure that enables the purchasing agent to approve and enlist a new vendor source. The best way is to develop a checklist and provide it to purchasing personnel to be used to help check out and verify a new vendor is worthy of being called approved. Then, follow through with close quality assurance inspection and verification when the part arrives. Set up a process by which vendors are placed on the list, audited regularly, and when necessary, removed from the list. It is a good idea to make a separate list and audit program for “outside service” vendors simply due to the difference in the type of regulations that service organizations are required to follow. An audit of service vendors will be quite different than one created for a parts supplier.

Types of suppliers

Anyone can sell you parts. At present, there is no regulation covering the sale of parts. Current rules regulate the installation of parts — not the sale of parts. This is why your company, as the parts installer, holds the responsibility of ensuring that the parts are approved. The best practice is to require your suppliers to include a statement of conformity with each order. A statement of conformity will help you hold the supplier liable; however, it will not eliminate your liability.

This content continues onto the next page...

We Recommend

  • Article

    What makes a part airworthy?

    Parts is Parts What makes an aircraft part airworthy? Joe Hertzler All new parts installed during the maintenance function have to be manufactured to one of the quality standards of 14...

  • Article

    Life-Limited Parts: Understanding the new rule

    Life-Limited Parts Understanding the new rule By Joe Hertzler A lthough many of you are aware of the recent addition to the regulations regarding life-limited parts, I would like to...

  • Article

    The Parts Process

    The Parts Process Framework for a parts management plan - from purchase to logbook entry - and everything in between By Joe Hertzler October 2000 The purchase, installation, and...

  • Article

    Baker's Dozen: The addition to Part 43

    The first three months of every year I travel around the country giving IA seminars to explain and defend the Federal Aviation Regulations.