Jack B. Buster

There are two PMA parts that could conceivably be affected by the design problems underlying this proposed action. In 1992 Parker Hannifin obtained PMA on P/N 3112002-139 by licensure to produce a replacement part for P/N 10-60871-139. In 1996 Crane Restoflex obtained PMA on P/N R 23582-0366 by licensure to produce a replacement part for P/N 10-60871-125. Under the wording of the proposed AD these parts, which presumably suffer the same defects as the OEM part, can be installed in place of the OEM parts in compliance with the AD. This is yet another example of the FAA's mindless parroting of OEM service bulletins without adequate research into areas not of concern to the OEM when producing the bulletin. It is, after all, the responsibility of the FAA to exerxise overisght and look beyond the self serving interests of those who write the service bulletins. OEM's universally ignore the existence of PMA in their bulletins even when they are responsible for issuing the licensure to manufacture these parts by PMA companies.. A simple check of the FAA''s own PMA database for these part numbers would have revealed the existence of PMA alternatives which was obviously not done by the AD writers The proposed AD should be modified to embrace PMA alternatives to the OEM part numbers cited. On a larger scale there should be developed and implemented procedures within all AD writing units to perform PMA research anytime a particular P/N is affected by a discovered defect. Think PMA - it is a part of today's world and will only become bigger in the future.