MT-Propeller Entwicklung GmbH Propellers

Comment on [Docket No. FAA-2005-20856; Directorate Identifier 2004-NE-25-AD] RIN 2120-AA64 It appears some further clarification and model identification is needed before the proposed action becomes final. Several of the models cited in the NPRM do not have type certificates available from the RGL database for download. Specifically the models cited in the NPRM without available type certificates are: MT MTV-2 MTV-5 MTV-10 MTV-11 MTV-17 MTV-20 MTV-22 MTV-24 Without the type certificates being available it is impossible to verify if these models even exist for U.S. registered aircraft. The NPRM has shifted applicability to those models manufactured before 1995. This appears to conflict with the dates of certain type certificates which are dated after 1995. If the type certificate was not issued until after 1995 it follows logically that no models were manufactured before 1995. Those type certificates dated after 1995 include: MTV-7 (P20BO) dated 19 May 2000 MTV-16 (P27BO) dated 9 February 2005 MTV-21 (P16BO) dated 9 September 1998 Perhaps there is some confusion generated because the service bulletin refers to U.S. and European certified propellers whereas the NPRM should address only those qualified under FAA rules. This would then be one more example of adopting verbatim manufacturer's service information without conducting the proper research to see what parts of the service information actually apply to U.S. qualified products. It actually isn't difficult to explain or understand that the first two digits of the manufacturer's serial number represent the year of manufacture and the last 3 digits represent the manufacturing sequence number within that year. Many Piper aircraft employ similar serial numbering schemes. Therefore, I request that the NPRM be reworked to include only those propeller models for which there are U.S. FAA type certificates and that only those dated prior to 1996 be included in the applicability listing or that some alternative applicability scheme is employed that is clear and unambiguous. Jack Buster Aviation Data Research and Modification and Replacement Parts Association