2003-10-01: High pressure turbine rotor (HPTR) rear shafts

2003-10-01 General Electric Company: Amendment 39-13144. Docket No. 2002-NE-24-AD. Applicability: This airworthiness directive (AD) is applicable to General Electric Company CF6-6 series turbofan engines. These engines are installed on, but not limited to McDonnell Douglas DC-10 series 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 (e) 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 should include specific proposed actions to address it. Compliance: Compliance with this AD is required as indicated, unless already done. To prevent cracks in high pressure turbine rotor (HPTR) rear shafts, which could result in uncontained engine failure and damage to the airplane, do the following: (a) Remove from service HPTR rear shafts, part numbers (P/Ns) 9137M13G01/G02/G03, 9138M22G01/G02/G09/G10, 9138M25G02, and 9687M22G04/G07/G10 in accordance with Table 1 as follows: Table 1.--HPTR Rear Shaft Removal Schedule If the rear shaft cycles-since-new (CSN) on the effective date of this AD are: Then remove the rear shaft (1) Fewer than 5,000 CSN Before exceeding 8,950 CSN. (2) 5,000 CSN or more, but fewer than 8,950 CSN Within 3,950 additional cycles-in-service (CIS) from the effective date of this AD or before 11,550 CSN, whichever occurs earlier. (3) 8,950 CSN or more At next HPTR rear shaft piece part exposure, or within 2,600 additional CIS, which- ever occursearlier. (b) After the effective date of this AD, do not install any HPTR rear shaft, P/Ns 9137M13G01/G02/G03, 9138M22G01/G02/G09/G10, 9138M25G02, or 9687M22G04/G07/G10, that has 8,950 or more CSN into an engine. (c) Except as provided in paragraph (a) of this AD, this action establishes a new, cyclic life limit of 8,950 CSN for HPTR rear shaft P/Ns 9137M13G01/G02/G03, 9138M22G01/G02/G09/G10, 9138M25G02, and 9687M22G04/G07/G10 which is published in Chapter 05-11-03 of CF6-6 Engine Shop Manual, GEK 9266. Definition (d) For the purpose of this AD, HPTR rear shaft piece-part exposure is defined as complete disassembly of the rear shaft from the HPTR structure using the manufacturer's engine manual. Alternative Methods of Compliance (e) 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 must submit their requestthrough 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 (f) Special flight permits may be issued in accordance with 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be done. Effective Date (g) This amendment becomes effective on June 17, 2003.