2008-10-14: Excessively corroded low pressure turbine disks stage 2 and stage 3

2008-10-14 Rolls-Royce Deutschland Ltd & Co KG (RRD) (formerly Rolls-Royce plc, Derby, England): Amendment 39-15521. FAA-2007-0037; Directorate Identifier 2007-NE-41-AD. Effective Date (a) This airworthiness directive (AD) becomes effective June 25, 2008. Affected ADs (b) None. Applicability (c) This AD applies to RRD TAY 650-15 turbofan engines that have a serial number listed in Table 1 of this AD, and low pressure turbine module M05300AA installed. These engines are installed on, but not limited to, Fokker F28 Mark 0100 airplanes. Table 1.--Affected TAY 650-15 Engines by Serial Number Engine Serial Number 17251 17255 17256 17273 17275 17280 17281 17282 17300 17301 17327 17332 17365 17393 17437 17443 17470 17520 17521 17523 17539 17542 17556 17561 17562 17563 17580 17581 17612 17618 17635 17637 17645 17661 17686 17699 17701 17702 17736 17737 17738 17739 17741 17742 17808 Reason (d) Strip results from some of the engines listed in the applicability section of this directive revealed excessively corroded low pressure turbine disks stage 2 and stage 3. The corrosion is considered to be caused by the environment in which these engines are operated. Following a life assessment based on the strip findings it is concluded that inspections for corrosion attack are required. The action specified by this AD is intended to avoid a failure of a low pressure turbine disk stage 2 or stage 3 due to potential corrosion problems which could result in uncontained engine failure and damage to the airplane. We are issuing this AD to detect corrosion that could cause stage 2 or stage 3 disk of the low pressure turbine to fail and result in an uncontained failure of the engine. Actions and Compliance (e) Unless already done, do the following actions. (1) Prior to accumulating 11,700 flight cycles (FC) since new, and thereafter at intervals not exceeding 11,700 FC of the engine,inspect the low pressure turbine disks stage 2 and stage 3 for corrosion in accordance with RRD Alert Service Bulletin TAY-72- A1524, Revision 1, dated September 1, 2006. (2) For engines that already exceed 11,700 FC on the effective date of this AD, perform the inspection within 90 days after the effective date of this AD. (3) When, during any of the inspections as required by paragraph (e)(1) of this directive, corrosion is found, replace the affected parts. The RRD TAY 650 Engine Manual--E-TAY-3RR, Tasks 72-52-23-200- 000 and 72-52-24-200-000 contains information on performing the inspection for corrosion and rejection criteria. Other FAA AD Provisions (f) Alternative Methods of Compliance (AMOCs): 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 EASA Airworthiness Directive 2006-0288, dated September 15, 2006, and RRD Alert Service Bulletin TAY-72-A1524, Revision 1, dated September 1, 2006, for related information. (h) Contact Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: jason.yang@faa.gov; telephone (781) 238-7747; fax (781) 238-7199, for more information about this AD. Material Incorporated by Reference (i) You must use Rolls-Royce Deutschland Alert Service Bulletin TAY-72-A1524, Revision 1, dated September 1, 2006, to do the actions required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation by reference 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 Deutschland Ltd & Co KG, Eschenweg 11, Dahlwitz, 15827 Blankenfelde-Mahlow, Germany; telephone 49 (0) 33-7086-1768; fax 49 (0) 33-7086-3356. (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.