Thursday, September 26, 2013

Parts and Traceability

Parts and Traceability

Note: An encounter with a Regulator Inspector prompted me to post this!

Undocumented Part Flow
I just recently dealt with a customer that was having problems with authenticating aircraft parts to the satisfaction of the regulator. It seems that parts need to have “type design” authentication. What is “type design” authentication? I started by going to the Canadian Aviation Regulation, CAR 571 Appendix H. “Part Identification: Verify that the part has certification or sufficient documentation, or both as applicable, to ascertain that it is a genuine part (i.e. nomenclature, part number, serial number, time in service) and that the part corresponds to that documentation.” 

The key to authenticating a part is the term “genuine part.” In order to have a genuine part we need to know what authority deems a part genuine. The standard for aircraft parts comes from the aircraft manufacturer. 

Obviously parts directly from the Original Equipment Manufacturer, OEM, itself will have “Traceability” to the genuine standard. The problem comes in when parts are not from the OEM. These parts must be evaluated against OEM requirements. “Using all available information, conduct an inspection of the part in accordance with the instructions for continued airworthiness or available type design data, or with both as applicable, for the part. It may be necessary to evaluate the part by comparison with a known authentic part. The evaluation process may require the use of hardness tests to determine heat treatment of the material. Procedures may be required to determine various material processes that may have been conducted on the material such as shot peening. Test all primary structural parts to determine that they are of the same material and in the same material condition as the type design product, either by comparison with the type design data (e.g. drawings) or by conducting comparison tests with a known authentic part.” In this the type design standard is the OEM specifications on the part from the drawing, material specs, and design requirements. Now the installer must evaluate, (i.e. hardness test, metallurgical tests, coating inspection...etc.) Traceability comes form the OEM specification. It is the job of the installer to provide objective evidence that the specifications are directly from the OEM. Parts that have no certification documentation can be evaluated to a known authentic part. The known authentic part become the standard and must be traceable to the OEM. ALL supporting documentation for the known authentic part must be supplied with the part for traceability purposes. 

Aircraft Parts 
In the photo to the right, ALL the parts pictured meet form, Fit and function requirements but, There is one part that definitely should NOT be installed into the aircraft. The “airworthiness” requirement goes beyond fit. The part must “authenticated” for materials, finishes and special processes. Traceability for all these parameters to the OEM is essential. In case you missed it, one of the parts is made of wood. Hardly suitable for aircraft use. 

The Traceability connection between parts & the OEM. 
Yes, parts can fit and seem to work. The problem arises as to function over time and with the stresses of the application of the part. In all this it is essential to have the Documentation that supports ALL the characteristics that "authenticate" the part. The key is the STANDARD that has been established by the OEM. The documentation for the parts must be traceable  to that standard. This may require a company to inspect and test the part to verify traceable specifications. 

Your thoughts.........

1 comment:

  1. Scenerio: Two Identical parts arrive at a overhaul shop.

    Part 1: arrives as part of a higher assembly. The higher assembly is traceable to last aircraft install but the part in question has no individual certification and you can no longer read any numbers or markings on the part

    2: Part arrives on its own, no documentation, but in a sealed OEM box. Upon opening the box all part numbers, cage codes and manufactures markings are visible.

    At this point which part is "more" genuine?
    Which part has greater traceability to manufacturer?
    Why can you simply assume the first part is genuine (assume that the original installer procured it from the OEM) with no actual supporting documentation other than the higher assembly previous install?

    Why can you simply overhaul part #1 and its is good but Part #2 requires a more extensive material and process inspection to substantiate it?


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