Traceability, Evidence, and Trust in the Aircraft Parts Industry

Traceability, Evidence, and Trust in the Aircraft Parts Industry

This is an article about complying with maintenance regulations. We rely much more on traceability and documentation, today, than we did twenty years ago. But as we rely more on traceability, it is important to reflect on why we rely on traceability, what is the purpose of the traceability, and based on these first two factors, what traceability should be acceptable.

Answering these three questions is an important exercise in identifying the right evidence to use in ascertaining an aircraft article’s airworthiness.

It is important to recognize that whether an article is airworthy is a simple binary function. It is or it isn’t. If we lose the documentation for the article, then this does not make the article unairworthy; but it may make it more difficult to prove the airworthiness. This simple binary function becomes more complicated when we consider the wide range of evidence used to demonstrate airworthiness. This use of evidence – this reliance on aviation documentation – is really an exercise in abstraction.

There are many areas of study that examine levels of abstraction. Philosophy of Language studies the difference between a word, the denotation of the word and the connotation of the word. Computer science languages are abstractions that translate into machine code written in ones and zeros. Numbers are abstractions that can stand for a quantity of physical objects. Even words are abstractions. The word “computer” used earlier in this paragraph, is an abstraction that denotes the thing you use for accessing online parts databases. We know what the word “computer” means, and we also know that the word cannot be confused with an actual computer.

Aviation mechanics deal with abstractions on a daily basis. When an aviation mechanic installs an aircraft article, that mechanic must ensure that the article installed will return the aircraft to a condition at least equal to original condition. That means the installation has to be airworthy.

It is possible to ensure airworthiness through direct measurement. We can measure the dimensions, metallurgical properties, and other key airworthiness properties of an aircraft article to verify its airworthiness. We can also rely on system elements; for example, we can rely on the fact that a production approval holder is not allowed to release an aircraft article from its quality system unless the article is airworthy. And when we start to rely on system elements – and the traceability associated with those elements, then we begin to engage in an exercise in abstraction, in which we rely on someone else’s documentation of a fact, rather than our own direct personal knowledge of that same fact.

How do we know that an aircraft article was released from a quality system? Typically, the installer has not seen the article released from the manufacturer’s quality system; instead, we rely on other evidence to demonstrate this fact. This sort of evidence can be based on someone with direct personal knowledge, like a production approval holder’s certification, or someone with indirect knowledge, like an air carrier that assured the airworthiness of the article at the time it was received by the carrier.

When we buy dish soap in the store, we typically don’t worry about whether it will work; we assume that the dish soap will function as expected. But airworthiness is so important that we have historically asked for evidence to support the allegations of airworthiness for aircraft articles.

The FAA’s rules specify a performance standard – namely that the installation must return the product to a condition at least equal to its original or properly altered condition; however, the FAA’s regulations do not specify what evidence is sufficient to prove the airworthiness of the article.

We can contrast this with the European aviation safety regulations managed by EASA. Those regulations specify the sort of evidence that must be received: in the European system, most aircraft articles need to be accompanied by an EASA Form 1. Other forms of evidence are thus typically insufficient (but implementations can vary).

In the United States system, there is no hard standard for what evidence is sufficient and what evidence is not sufficient. The FAA’s chief counsel’s office has made it clear that the evidence of airworthiness can be generated through test and analysis of an article (to make sure it meets the appropriate airworthiness standards) or through reliance on other persons. One source of evidence can be manufacturers. In recent years, the FAA has changed its rules to permit production approval holders (PAHs) to issue the FAA Form 8130-3 as a “birth record” for new articles. This is great for newer articles, but the authority did not exist until recently, and many older articles were not documented at birth with 8130-3 tags.

We can still rely on the regulatory structure that requires the PAH to ensure airworthiness of articles before they are released from the quality assurance system. This means if you buy an aircraft article direct from the PAH, then you know that it was airworthy. And if the chain of commerce suggests that the article was released by the PAH, then this also provides evidence of airworthiness. This can be accomplished using something other than back-to-birth traceability (back-to-birth is, of course, a commercial norm for life-limited parts but is usually not appropriate for other aviation articles).

FAA guidance has also suggested that other forms of PAH evidence may be acceptable to “provide evidence that an article was produced by a manufacturer holding an FAA-approved manufacturing process.” This includes PAH documents such as shipping tickets and invoices. It also includes unregulated PAH markings, like standard inspection stamps. The industry has also relied on commercial features like PAH packaging to provide evidence of source.

Aviation has a tradition of relying on evidence to demonstrate airworthiness, and a corollary tradition of relying on trusted sources, like certificate holders, to provide that evidence. This has meant that we rely on the accuracy of statements from certificate holders to support our airworthiness findings. This evidence can come from manufacturers, from repair stations, and even from air carriers. As certificate holders, we trust their statements. So, if an air carrier surpluses an article, and provides evidence that the article is new, and was produced by a particular PAH, then we have a tradition of trusting that evidence. This evidence has often taken the form of a statement from the air carrier, like a packing list identifying the identity and condition of the articles in a surplus lot. The industry’s trust is based, in article, on the fact that the government typically approves the air carrier’s receiving inspection system (the FAA has an entire advisory circular explaining what the system should look like).

How important is trust to our industry? It is so important the we reserve the most stringent punishments for those who violate that trust.

Falsehoods have traditionally reflected a disqualification to hold an FAA certificate. Even if this was not evident from case law, I would know it because Judge Geraghty of the NTSB administrative law court would remind me of this during our encounters – he always felt it important to remind the industry that inaccuracy and falsehood are the most terrible of sins in the aviation world. When I was a young lawyer, the Judge would explain to me that the FAA relies on documentation to perform its oversight functions. If that documentation is not accurate, or is misrepresented, then this undermines the essence of the FAA’s oversight role.

Violating this trust through fraud or misrepresentation yields severe penalties. It can lead to a lifetime ban from the industry, and criminal penalties can range from 15 years for merely misrepresenting the quality of an aircraft article to life in prison if that same article malfunctions.

Our aircraft articles system is based on this sort of trust. We trust that FAA-approved manufacturers will produce airworthy articles. In the United States, this trust is based on the FAA’s approval of the design (which verifies that the design meets FAA safety standards), and the correlative FAA approval of the production system (which verifies that the production quality system is sufficient to ensure that articles produced under the system will meet the FAA-approved design). We trust that certificate holders will provide accurate statements about the articles that were received into their systems.

Over the past twenty years, the distributor accreditation system has infused an added element of trust into the system. Accredited distributors typically pass along necessary elements of the evidence that they receive to the next partner in the chain of commerce; they also retain all received documents in their system in order to maintain the audit trail. Although traditionally the accredited distributor has not make airworthiness determinations, the FAA has started to nominate FAA designated airworthiness representatives (DARs) who are able to work in an accreditation environment, review the information, and issue an 8130-3 tag on behalf of the FAA when the evidence is sufficient to show that the article is airworthy

The system for confirming the airworthiness of aircraft articles at the time of installation remains an evidence-based system. Sources like the FAA’s accreditation advisory circular provide guidance about what sort of evidence may be acceptable, but ultimately the installer must decide what sort of evidence is credible.
Next time you look at a traceability document, think about who you are trusting and why.

Disclosure: Jason Dickstein is the General Counsel of the Aviation Suppliers Association, and was a member of the EASA rulemaking committee described in this article.

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