2011-18-01: LPT rotor stage 3 disks

Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39--AIRWORTHINESS DIRECTIVES 0 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. Sec. 39.13 [Amended] 0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): 2011-18-01 General Electric Company: Amendment 39-16783; Docket No. FAA-2010-0998; Directorate Identifier 2010-NE-29-AD. Effective Date (a) This AD is effective September 26, 2011. Affected ADs (b) None. Applicability (c) This AD applies to General Electric Company (GE) CF6-45A, CF6-45A2, CF6-50A, CF6-50C, CF6-50CA, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2D, CF6-50E, CF6-50E1, and CF6-50E2 series turbofan engines, including engines marked on the engine data plate as CF6-50C2-F and CF6-50C2-R, with a low-pressure turbine (LPT) rotor stage 3 disk that has a part number (P/N) listed in Table 1 of this AD installed. Table 1--LPT Rotor Stage 3 Disk P/Ns ------------------------------------------------------------------------ ------------------------------------------------------------------------ 1473M90P01 1473M90P02 1473M90P03 1473M90P04 1479M75P01 1479M75P02 1479M75P03 1479M75P04 1479M75P05 1479M75P06 1479M75P07 1479M75P08 1479M75P09 1479M75P11 1479M75P13 1479M75P14 9061M23P06 9061M23P07 9061M23P08 9061M23P09 9061M23P10 9061M23P12 9061M23P14 9061M23P15 9061M23P16 9224M75P01 ................ ................ ------------------------------------------------------------------------ Unsafe Condition (d) This AD results from seven reports of uncontained failures of LPT rotor stage 3 disks and eight reports of cracked LPT rotor stage 3 disks found during shop visit inspections. We are issuing this AD to prevent LPT rotor separation, which could result in an uncontained engine failure and damage to the airplane. Compliance (e) You are responsible for having the actions required by this AD performed at each shop visit after the effective date of this AD, at which the LPT module assembly is separated from the engine. Initial Inspection (f) At the next shop visit after the effective date of this AD, clean and fluorescent-penetrant inspect the LPT rotor stage 3 disk forward spacer arm, including the use of a wet-abrasive blast to eliminate residual or background fluorescence before inspecting. You can find guidance on cleaning the disk and performing the FPI in the CF6-50 Engine Manual, GEK 50481 72-57-02. Repetitive Inspection (g) Thereafter, clean and inspect the LPT rotor stage 3 disk forward spacer arm, as specified in paragraph (f) of this AD, at each engine shop visit that occurs after 1,000 cycles since the last FPI of the LPT rotor stage 3 disk forward spacer arm. (h) If a crack or a band of fluorescence is present, remove the disk from service. Definitions (i) For the purpose of this AD: (1) The LPT module assembly is defined as consisting of turbine mid-frame, LPT stage 1 nozzle, LPT stator cases and vanes, LPT rotor, and turbine rear frame. (2) An engine shop visit is the induction of an engine into the shop for maintenance involving the separation of the turbine mid- frame forward flange from the compressor rear frame aft flange, except that the separation of these engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit. Alternative Methods of Compliance (j) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Related Information (k) For more information about this AD, contact Tomasz Rakowski, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: (781) 238-7735; fax: (781) 238-7199; e-mail: tomasz.rakowski@faa.gov. Material Incorporated by Reference (l) None.