Because of the FAA’s robust design and production approval system, one
strategy for demonstrating airworthiness of an aircraft part is to show that it was produced under FAA design and production approval. This demonstrates that the part was airworthy at the time it left the production approval holder’s quality system; all the installer needs to do is (1) confirm that the design and production approval remains valid (e.g. there is no airworthiness directive applicable that prevents use of the part), and (2) confirm that the part has not suffered damage or degradation (potentially changing its physical characteristics so that its airworthiness is not longer assured). Documentation recommendations from the FAA can be found in advisory
circulars, Chief Counsel’s opinion letters, and other FAA guidance. The FAA’s guidance makes it clear that new parts may be accompanied by a variety of traceability documents to verify their source, like:
ƒ shipping tickets or invoices from the manufacturer ƒ manufacturer’s certificate of conformance ƒ evidence of direct ship authorization ƒ FAA 8130-3 tag or acceptable comparable foreign tag
The FAA’s guidance also specifies that in the absence of identifying
documentation, the markings required by Part 45 may also suffice to identify the origin of the part. This would include “PMA” markings and “TSOA” markings. The FAA has established preferred traceability standards for parts obtained
through distributors (the standards are published in AC 00-56, the Voluntary Industry Distributor Accreditation Program). These standards are not supported by any regulation so they are not enforceable, but reliance on this sort of documentation has become an industry norm. Where there is no documentation and no part markings, then this does not
mean that the part is unairworthy. Instead, it means that the airworthiness of the part must be established using some other mechanism. This typically means a three step process:
1. Identify the airworthiness characteristics of the part. These characteristics may be required by regulation or they may be design requirements. Form, fit and function are at the root of this analysis but for more complex parts there are typically other features that need to be identified.
2. Develop a series of tests and inspections that will prove whether or not the part meets each of the airworthiness characteristics identified in step one. In some cases, the overhaul tests and inspections published by the manufacturer may provide guidance in identifying the appropriate tests and inspections. The tests must be sufficiently robust to demonstrate whether the part meets the requirements of its approved design and is in a condition for safe operation.
3.Perform each of the identified tests and inspections, and analyze the results to ascertain whether the part meets the appropriate airworthiness characteristic and standards that are relevant to its intended use.
If this process confirms that the part meets its approved design and is in a
condition for safe operation, then it may be installed as an airworthy part. Obviously, this test-and-analysis method of identifying airworthiness is inefficient
for most purposes. That is why documentation or other evidence showing that the part was originally produced by a production approval holder is so valuable. In order to obtain a FAA design approval, the manufacturer had to demonstrate airworthiness to the FAA and in order to obtain a production approval the manufacturer had to demonstrate that the quality system would produce parts that met the standards of the approved design. The net result is that when the installer relies on traceability to a manufacturer, what is really happening is that the installer is relying on the FAA’s prior design-and-production approval findings related to the approved manufacturer. Even though traceability is not legally required, there are good reasons to rely on adequate traceability to support the installer’s airworthiness findings. AM
Aviation Maintenance |
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