2006-NE-33-AD - General Electric Company CF34-10E Series Turbofan Engines

Comment on [Docket No. FAA-2006-25896; Directorate Identifier 2006-NE-33-AD] This proposed airworthiness directive involves at least two potential problem areas in dealing with defective components. The first is the FAA tendency to adopt manufacturers' service documents as authoritative and comprehensive treatment for a detected problem without consideration of aspects that may reach beyond the manufacturers' immediate concerns. In this instance there exist at least two alternatively approved substitution parts for the defective parts mentioned in the document. Argo-Tech holds PMA on P/N's 837600-3 and 837600-4 which are approved direct replacements for the OEM P/N's 2043M12P03 and 2043M12P04. Indeed, it may be that the Argo-Tech parts are identical with the OEM parts, but since they are numbered differently the proposed airworthiness directive will exclude them. Even if not identical, the proposed regulation needs to address the fact that PMA replacement parts presently exist for those now determined to be defective and incorporate language that will prevent defective PMA parts from continuing in service. MARPA continues to believe and suggest that language be developed and used that will bring defective PMA parts under the regulatory umbrella. Comments to this effect have, in the past, been addressed by the FAA stating to the effect "when we know of PMA parts existence, . . . " However, airworthiness directives are legal documents that are interpreted as questions of law. Factual elements, such as the FAA's knowledge or intent, etc., are not probative issues and have no bearing on the force and effect on the AD. In short, it doesn't matter what the FAA knows or doesn't know, intends or doesn't intend; the AD must stand on its own bounded by the figurative four corners of the document. Likewise, the FAA can not rely on the OEM to bring to the FAA's attention that PMA parts may or may not exist for a defective OEM part. The solution is to develop and use language that will reach beyond the manufacturers' service documents and consider that PMA parts may exist for those now determined to be defective. In response to repeated MARPA comments on this issue, the Small Airplane Directorate has adopted language that effectively addresses MARPA's concerns on this issue. See 2005-26-14 as one example. The second issue raised by this proposed action is the flawed availability of PMA information. MARPA has spent considerable time identifying PMA data that has never flowed from the various MIDO's to AIR-140 where it can be incorporated into the RGL PMA database. In fact, we have concluded from actual research that approximately 30% of all PMA data remains at the MIDO level without ever being supplied to AIR-140. The existence of such a gap in PMA information emphasizes the need to develop applicability language that is not dependent upon present knowledge, but addresses the issue in a global sense. We do note that the proposed action does not require installation of a single OEM part as a solution to the airworthiness problem, but leaves open the possibility of PMA part installation. We commend the FAA on this forward thinking approach. Jack Buster AD Committee Modification and Replacement Parts Association