2010-17-10: Rear cooling air holes

2010-17-10 Rolls-Royce plc: Amendment 39-16402. Docket No. FAA-2009- 1157; Directorate Identifier 2009-NE-26-AD. Effective Date (a) This airworthiness directive (AD) becomes effective September 27, 2010. Affected ADs (b) None. Applicability (c) This AD applies to Rolls-Royce plc RB211-22B series and RB211-524B4-D-02, RB211-524D4-19, RB211-524D4-39, RB211-524D4-B-19, RB211-524D4-B-39, RB211-524D4X-19, and RB211-524D4X-B-19 model turbofan engines. These engines are installed on, but not limited to, Boeing 747 series and Lockheed L-1011 series airplanes. Reason (d) This AD results from: Several low pressure turbine (LPT) shafts have been found with cracks originating from the rear cooling air holes. The cracks were found at normal component overhaul, by the standard Magnetic Particle Inspection (MPI) technique defined in the associated engine manual. The cracks have been found to initiate from corrosion pits. Propagation of a crack from the rear cooling air holes may result in shaft failure and subsequently in an uncontained Low Pressure Turbine failure. For the reasons stated above, this AD requires the inspection of the affected engines' LPT shafts and replacement of the shaft, as necessary. We are issuing this AD to detect cracks, initiated by corrosion pits, originating from the rear cooling air holes, which could result in shaft failure and subsequently in an uncontained failure of the LPT and damage to the airplane. Actions and Compliance (e) Unless already done, do the following actions. Initial Inspection Requirements (1) At the next engine shop visit after the effective date of this AD when the LPT shaft is completely disassembled to piece-part level, inspect the LPT shaft using paragraphs 3.A.(1)(a) through 3.A.(4)(l) of the accomplishment instructions of Rolls-Royce Service Bulletin RB.211-72-AF336, dated October 24, 2007. Repetitive Inspection Requirements (2) Thereafter, reinspect the LPT shaft using paragraphs 3.A.(1)(a) through 3.A.(4)(l) of the accomplishment instructions of Rolls-Royce Service Bulletin RB.211-72-AF336, dated October 24, 2007 and the following schedule in Table 1 of this AD: Table 1--Repetitive Inspection Interval by Engine Model Engine Model Maximum Time Between Inspections (engine cycles) (i) RB211-22B Series, all models. 3,500. (ii) RB211-524B4-D-02. 4,000. (iii) RB211-524D4-19, RB211-524D4-39, RB211-524D4-B-19, RB211-524D4-B-39, RB211-524D4X-19 and RB211-524D4X-B-19. At the next engine shop visit after the last inspection. Remove Parts With Cracks (3) Remove cracked LPT shafts, found using paragraphs (e)(1) or (e)(2) of this AD, from service before further flight. Definitions (4) For the purpose of this AD, an engine shop visit is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges. The separation of engine flanges solely for the purposesof transportation without subsequent engine maintenance does not constitute an engine shop visit. Alternative Methods of Compliance (AMOCs) (f) The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Related Information (g) Refer to MCAI EASA Airworthiness Directive 2007-0310 R1, dated January 8, 2008, for related information. (h) Contact Alan Strom, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: alan.strom@faa.gov; telephone (781) 238-7143; fax (781) 238-7199, for more information about this AD. Material Incorporated by Reference (i) You must use Rolls-Royce Service Bulletin RB.211-72-AF336, dated October 24, 2007, to do the actions required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation byreference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. (2) For service information identified in this AD, contact Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, United Kingdom; telephone 044 1332 242424; fax 044 1332 249936. (3) You may review copies at the FAA, New England Region, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.