2001-20-01: Compressor Bleed Valve Assembly

2001-20-01 Pratt & Whitney Canada: Amendment 39-12447. Docket 2000-NE-26-AD. Applicability This airworthiness directive (AD) applies to PT6A-25C and -114A Series turboprop engines, that have incorporated P&WC S.B. 1510, which are installed on but not limited to Pilatus PC-7 and Cessna 208 Caravan airplanes. Note 1: This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request shouldinclude specific proposed actions to address it. Compliance Compliance with this AD is required as indicated, unless already done. To detect wear on the compressor bleed valve assembly cover, guide pin shaft, cotter pin, and to detect particles from diaphragm wear, which may cause valve orifice blockage, resulting in a loss of power, an inability to accelerate the engine, and an in-flight shutdown, do following: Initial and Repetitive Inspections (a) Perform an initial visual inspection of the compressor bleed valve assembly components within 150 flight hours after the effective date of this AD in accordance with Accomplishment Instructions, Section 3A through 3B of Pratt & Whitney Canada (PWC) Service Bulletin (SB) PT6A-72-1574, Revision 2, dated October 14, 1999. (b) Thereafter, perform repetitive visual inspections of the compressor bleed valve assembly components within 600 flight hours after the last inspection in accordance with Accomplishment Instructions, Section 3A through 3B of PWC SB PT6A-72-1574, Revision 2, dated October 14, 1999. Terminating Action (c) For PT6A-114A series turboprop engines, replacement of compressor bleed valve assemblies at the next shop visit, with the redesigned valve assembly, in accordance with PWC SB PT6A-72-1588, dated February 18, 2000 or PWC SB PT6A-72-1581, Revision 1, dated February 1, 2000, is considered terminating action for the inspection requirements of this AD. This action must be done at the next shop visit but no later than five years from the effective date of this AD. (d) For PT6A-25C series turboprop engines, replacement of compressor bleed valve assemblies with the redesigned valve assembly, at the next shop visit, in accordance with PWC SB PT6A-72-1589, dated November 1, 2000, is considered terminating action for the inspection requirements of this AD. This action must be done at the next shop visit but no later than five years from the effective date of this AD. Definition (e) For the purpose of this AD, a shop visit is defined as when the subassembly (i.e. module, accessories, components or build groups) is disassembled and access is available to the compressor bleed valve assembly. Alternative Methods of Compliance (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. Special Flight Permits (g) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane toa location where the requirements of this AD can be accomplished. Documents That Have Been Incorporated by Reference (h) The inspections and replacement shall be done in accordance with the following Pratt & Whitney Canada service bulletins: Document No. Pages Revision Date SB PT6A-72-1574 Total pages: All 2 Oct. 14, 1999. 3 SB PT6A-72-1581 Total pages: 12 All 1 Feb. 1, 2000. SB PT6A-72-1588 Total pages:12 All Original Feb. 18, 2000. SB PT6A-72-1589 Total pages: 10 All Original Nov. 1, 2000. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Pratt & Whitney Canada, 1000 Marie-Victorin, Longueuil, Quebec, Canada J4G1A1. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC. Note 3: The subject of this AD is addressed in Transport Canada Airworthiness Directive CF-99-23, dated September 14, 1999. Effective Date (i) This amendment becomes effective on November 5, 2001.