MacLeod-2-ARSA 2009

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U.S. Department of Transportation Federal Aviation Administration SEP 3 2009 Sarah MacLeod Executive Director Office of the Chief Counsel Aeronautical Repair Station Association 121 North Henry Street Alexandria, VA 22314-2903

Dear Ms. MacLeod:

800 Independence Ave .. S.W .

Washington, D.C. 20591 Thank you for your request of October 27, 2007, regarding compliance with Airworthiness Directive (AD) 2003-12-07. We apologize for the delay in responding to your letter. Your letter indicates that your members have experienced problems while doing work associated with compliance with the AD. You indicate that the AD requires the inspection of certain engine disks after their protective coating has been removed, and replacement if the required inspection finds corrosion pits or cracks beyond serviceable limits. The FAA incorporated Pratt and Whitney Alert Service Bulletin A643 l (ASB) for the procedures to be used in performing the required inspection and for determining the serviceable limits of inspected disks. You note that the ASB includes instructions on the removal and inspection of disks in accordance with several Pratt & Whitney engine manuals.

You note that the service bulletin continues with instructions not included in the AD, including recommended replating/recoating methods for disks that are found acceptable after inspection. The ASB calls for recoating in accordance with another Pratt & Whitney service bulletin not incorporated in the AD, and plating according to Pratt & Whitney engine manuals not incorporated in the AD. In turn, the engine manuals call out instructions for the plating according to a Standard Practices Manual that was not incorporated, and that manual has two parts that refer to plating, one of which indicates that plating be done by a Pratt & Whitney approved source, with a list of 13 companies that Pratt & Whitney has approved to do the work.

You conclude that the requirements of the AD are met when a repair station strips and inspects each disk in accordance with the incorporated ASB. If no unacceptable pitting or cracking is found on inspection, no further action is required under the AD. You find that the AD does not require certain maintenance for those disks that pass inspection.

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We agree with your conclusion that the requirements of the AD are met when the disks are stripped and inspected as instructed in the ASB. The ASB also calls out the serviceable limits. We did not incorporate the other portions of the ASB that include specific return to service instructions or by extension, the companies approved by Pratt & Whitney to accomplish the replating work. When no return to service instructions are included in an AD, the standard requirements for returning a part to service apply as required under 14 CFR parts 43 and 145. The FAA is sensitive to the fact that service bulletins and other materials issued by manufacturers often contain extraneous instructions and methods that are not relevant to accomplishment of an AD. Only the stated portions of incorporated material are required for compliance with a regulation.

Your letter continues, noting that in 2006, the FAA issued Unapproved Parts Notice (UPN) 2006-00178. That UPN advised that a suspected unapproved parts investigation revealed a problem with Aircraft Power & Service, Inc (APS), a Durant, OK repair station. The UPN indicates that APS subcontracted disk plating work to a repair station that was not approved by Pratt & Whitney as described in its overhaul manual. The UPN advises that components serviced by APS not be installed until a determination can be made regarding each component's eligibility for installation.

Your letter indicates that there is no evidence that the replating work in question was performed improperly, and that the UPN states only that it was not done by a Pratt & Whitney approved facility. You state that the owners of the disks affected by the UPN "are constantly questioned as to whether the work performed can be used to establish compliance with the AD." You conclude that the work performed by APS under the AD was done properly, that the replating was performed as required by regulation, and that the UPN should be withdrawn.

We have concluded that the issues surrounding the UPN are not a proper subject for legal interpretation. The Office of the Chief Counsel does not have the authority to withdraw notices issued by other offices within the agency. Reconsideration of the UPN must be addressed to the Flight Standards Service, which is the office in which that program resides. Finally, you asked us to confirm that "in all cases, approval by a manufacturer is not required under§ 43. IJ(a) even if the maintenance manual or ICA "requires" such approval provided the method, technique or practice used returns the article to at least its original or properly altered condition as required by§ 43.13(b)." We can clarify that compliance with any manufacturer provided instructions, recommendations, or use of manufacturer-approved sources identified in their maintenance manuals or instructions for continued airworthiness is one way to satisfy § 43. lJ(a). Other methods, techniques and practices not necessarily 'approved' by the manufacturer may be used to satisfy §43. lJ(a) provided that they are acceptable to the Administrator.

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We trust that this interpretation responds to the various issues raised in your inquiry. If you have any questions, please contact my staff at 202-267-3073. This response was prepared by Karen Petronis, Senior Attorney for Regulations in my office, was coordinated with counsel in the Engine and Propeller Directorate, and was coordinated with staff in the Aircraft Certification Service.

Sincerely,

R&.;acft.:n)/J-Assistant Chief Counsel for Regulations, AGC-200