Cessna Model 750 Airplanes

Comment on 2005-NM-069-AD (2005-09-01) This airworthiness directive (AD) requires inspection and/or replacement of an auxiliary power unit (APU) fuel line on certain Cessna model 750 aircraft. Corrective action requires compliance with Cessna Alert Service Letter ASL750-49-09, Revision 2, dated March 10, 2005. The APU fuel tube on certain aircraft must be replaced pursuant to the following statement in the airworthiness directive: The replacement APU fuel tube must be a new APU fuel tube having part number 6756605-23. 14 CFR 21.303 (PMA) provides a statutory basis for the manufacture and installation of parts in lieu of original parts. Therefore, any requirement in the subject AD to install a certain part number to the exclusion of all other part numbers is at variance with FAR 21.303. Parts now existing or approved in the future may be the PMA equivalent of the Cessna part specified in the AD. Further, the use of parts manufactured under 21.303 is approved by statute and is not, as some AD writers believe, an alternative method of compliance requiring further approval. Therefore, this commenter, Modification and Repair Parts Association (MARPA), requests the following: That the language cited above be modified by appending the term "or PMA equivalent part number." Jack Buster AD Committee