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 approval for return to service of the installed...


The Parts Process

Framework for a parts management plan - from purchase to logbook entry - and everything in between

Joe HertzlerBy Joe Hertzler

October 2000

The purchase, installation, and approval for return to service of the installed aircraft parts, combined with inspections, makes up the heart of the aircraft maintenance function. The regulations that govern replacement parts have not received any appreciable changes since their conversion from CAR to FAR as part of the Aviation Act of 1958. Yet, many of the regulations, industry standards, and FAA enforcement policies, have changed dramatically over the past decade.

What makes a good part?
A good part is one that has been through at least one FAA-approved quality assurance process (Quality Screen) and has successfully passed the inspection criteria of that process.
As a maintenance organization, certificated Repair Station, or otherwise, you are responsible for ensuring that all parts installed during the maintenance function meet the certification requirements of 14 CFR Part 21.303. Following are the five possible Quality Screens for NEW parts.
1. PMA - Parts Manufacturing Approval - Applies only to specific part numbers and is usually associated with STC or a direct replacement (NON OEM) part.
2. PAH - Parts manufactured under the production certificate of 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 non-programmable 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. Such parts are not exempt from FAA approval for complex fabrication.
Although 14 CFR Part 21 addresses new replacement parts, a Quality Screen is required regardless of whether the part is new or used. The quality of a used part is identified by its approval for return to service covered under 14 CFR Part 43, (Reference part 43.13 and 43.9).

The approved vendor list
The first step is to develop a simple list of parts vendors that you have determined will send you good parts when you order from them. Providing 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 provide a procedure that enables the purchasing agent to enlist a new vendor source. Develop a checklist and provide it to purchasing personnel to be used to help check out a new vendor. 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.

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