AD 89-01-02

89-01-02 GENERAL ELECTRIC: Amendment 39-6082.

Applicability: General Electric (GE) CF6-50 series turbofan engines.

Compliance: Required as indicated, unless already accomplished.

To prevent failure of high pressure turbine (HPT) stage 2 disks, Part Numbers (P/N) 9045M35P15, 9045M35P17, and 9045M35P18, Serial Numbers MTU00001 through MTU00973 inclusive, except the following serial numbers (listed in alphanumeric order): MTU00541, MTU00562, MTU00563, MTU00634, MTU00646, MTU00652, MTU00654, MTU00668, MTU00671, MTU00672, MTU00675, MTU00756, MTU00777, MTU00778, MTU00782, MTU00783, MTU00808, MTU00820, MTU00827, MTU00829, MTU00846, MTU00847, MTU00849, MTU00857, MTU00875, MTU00877, MTU00881, MTU00884, MTU00885, MTU00887, MTU00888, MTU00893, MTU00896, MTU00899, MTU00905, MTU00906, MTU00908, MTU00909, MTU00910, MTU00911, MTU00912, MTU00914, MTU00916, MTU00917, MTU00918, MTU00919, MTU00920, MTU00921, MTU00933, MTU00935, MTU00953, MTU00959, MTU00960, MTU00961, accomplish either (a) or (b) below:

(a) Rework the forward embossment in accordance with GE Service Bulletin (SB) 72-947, dated August 17, 1988, at the next HPT module exposure, not to exceed 3,800 cycles since last installation in an engine. However, for disks which have accumulated 3,500 or more cycles since last installation in an engine on the effective date of this AD, comply with the provisions of this paragraph at the next HPT module exposure, or within the next 300 cycles from the effective date of this AD, whichever occurs first.

(b) (1) Perform double fluorescent penetrant inspection (FPI) in accordance with GE SB 72-947, dated August 17, 1988, at the next HPT module exposure, not to exceed 3,800 cycles since last installation in an engine. However, for disks which have accumulated 3,500 or more cycles since last installation in an engine on the effective date of this AD, comply with the provisions of this paragraph at the next HPT module exposure, or within the next 300 cycles from the effective date of this AD, whichever occurs first.

(2) Rework the forward embossment in accordance with the above noted SB, at or prior to accumulating 2,500 cycles since passing the double FPI noted in this paragraph.

NOTE: HPT module exposure is defined as any removal of the HPT rotor and HPT stage 2 nozzle assembly from the engine core (high pressure compressor and compressor rear frame).

(c) In complying with either paragraph (a) or (b) above, do not exceed already published life limits.

(d) Disks found cracked while complying with either paragraph (a) or (b) above, are not eligible for either rework, or reinstallation or operation in an engine.

(e) Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803.(f) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD may be accomplished.

(g) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, may adjust the compliance schedules specified in this AD.

GE SB 72-947, dated August 17, 1988, identified and described in this document is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552 (a) (1). All persons affected by this directive who have not already received the engine manufacturer's SB may obtain copies upon request to General Electric Company, Technical Publications Department, 1 Neumann Way, Cincinnati, Ohio 45215. This document also may be examined in the Office of the Assistant Chief Counsel, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803, Room 311, Rules Docket No. 88-ANE-31, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays.

This amendment (39-6082, AD 89-01-02) becomes effective on December 29, 1988.