Most of the details of the type design are considered by the manufacturer as proprietary data and are not available to the public. Aircraft manufacturers have prevented the FAA from releasing any of their proprietary data. There is no way that conformity to the type design can be accomplished without the data that is in the hands of the manufacturer and will not be released. Bare type certificate data sheets are summaries and are a shortened listing of details in the type certificate and do not prove or show that an aircraft is airworthy or that it conforms to a particular type certificate.
The NTSB early on said that since the FAA did not introduce type design data into evidence in some cases, they were dismissed as not proved. In other cases the FAA has had experts testify that any damage to an aircraft or modification would in fact alter the type design contrary to the law. It’s gone both ways depending on who was on the Board.
An interesting argument
Some commentators also have suggested that the failure of the FAA to define airworthiness in the FAR without first publishing it in the Federal Register, makes the many sections of the FAR that rely on this definition unenforceable. A person must have timely and actual formal notice of such matters that are required to be published in the Federal Register (like a new definition) and a comment period established. (5 USC 552) ... At this late stage, publishing this definition in an FAA handbook or in an NTSB Order cannot satisfy this requirement without publishing in the Federal Register and allowing comment. It is suggested that it is unlawful that airmen and air facilities are held responsible for an unpublished definition.
In one case, argued in a U.S. District Court (civil penalty case), a mechanic at the request of an owner, installed a Bendix magneto on an aircraft rather than a Slick which was called for in the type certificate data sheet. Slick was the only magneto listed for installation. A case was brought against the mechanic that he had failed to install a magneto that conformed to the data sheet and therefore violated Far 43.13(b). The mechanic in defense argued that there was no requirement under the FARs to conform to the data sheet because the FARs do not state that mechanical work must conform with the data sheet. Both sides made a motion for summary judgment on the face of the pleadings. The FAA out of an abundance of caution, probably fearing it was going to lose and did not want to create unwanted precedent, agreed to dismiss the case in exchange for an agreement by him not to seek attorney fees and costs. There was no final decision on this case.
Further Board statements
The FAA today does not rely solely on the definition that has for so long been used. It can usually find another FAR section to support its action. The concept of reasonableness also seems to have crept into decisions in many cases. In one case the NTSB stated its decision in the following way: “We are not convinced that every potential hazard created by something carried on an aircraft automatically warrants the conclusion that the aircraft was rendered unairworthy …”
And in another case the Board has stated, “We do not agree that every scratch, dent, pinhole of corrosion, missing screw, or other defect, no matter how minor or where located on the aircraft, dictates the conclusion that the aircraft’s design, construction, or performance has been impaired by the defect to a degree that the aircraft no longer conforms to its type certificate. In this case, the Administrator essentially made no effort to show that the alleged defects or discrepancies had an adverse impact on the level of safety that an aircraft’s conformity with its type certificate is intended to insure, or to counter the substantial evidence adduced by the respondent that they had not had such an impact.”
Finally, as a footnote to this case the Board stated further, “To the extent that the relevance of a specific mechanical condition or defect is neither self-evident nor addressed in an appropriate maintenance manual or other reference, we perceive no reason why a properly trained mechanic should not be free to determine whether the airworthiness of an aircraft exhibiting such a condition or defect has been compromised. Indeed, we assume aircraft mechanics are called upon routinely to make such determinations.”
It seems clear in these cases that minor wear and tear, as well as minor alterations, will not make an aircraft unairworthy. I believe the arguments will continue until the FAA clears up the issue with some additional finality, of just what constitutes airworthiness. Comments to email@example.com.
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There are two very important pieces of paper that are issued by the United States Government that, once issued, are usually forgotten by the aviation community.