AD 91-15-03 ACTIVE

91-15-03 GENERAL ELECTRIC COMPANY: Amendment 39-7066. Docket No. 91-ANE- 25.

Applicability: General Electric Company (GE) CF6-6 series turbofan engines installed on, but not limited to, McDonnell Douglas DC10-10 aircraft.

Compliance: Required as indicated, unless previously accomplished.

To prevent an uncontained engine failure and damage to the aircraft, accomplish the following:

(a) Remove from service stage 1 fan disks identified by serial number (S/N) in Group A, Figure 3 of GE CF6-6 Service Bulletin (SB) 72-962, Revision 3, dated May 22, 1991, within the next 10 cycles in service (CIS) after the effective date of this AD and replace with a serviceable part.

(b) Eddy current inspect in accordance with GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, the bore forward corner of stage 1 fan disks identified by S/N in Group B, Figure 3 of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, as follows:

(1) For disks which on the effective date of this AD have not received an eddy current inspection in accordance with the Accomplishment Instructions of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, inspect in accordance with the following schedule:

(i) Within the next 100 CIS after the effective date of this AD, for disks which on the effective date of this AD have accumulated 1,250 CIS or greater since accomplishing the immersion ultrasonic inspection in accordance with the Accomplishment Instructions, paragraph 2.B. of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991.

(ii) Within the next 100 CIS after the effective date of this AD or prior to accumulating 1,250 CIS since the immersion ultrasonic inspection, whichever comes later, for disks which on the effective date of this AD have accumulated less than 1,250 CIS since accomplishing the immersion ultrasonic inspection in accordance with the Accomplishment Instructions, paragraph 2.B. of GE SB 72-962, Revision 3, dated May 22, 1991.

(2) For disks which on the effective date of this AD, have received an eddy current inspection in accordance with the Accomplishment Instructions of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, inspect in accordance with the following schedule:

(i) Within the next 100 CIS after the effective date of this AD for those disks which on the effective date of this AD have accumulated 1,500 CIS or greater since accomplishing the immersion ultrasonic inspection in accordance with the Accomplishment Instructions, paragraph 2.B. of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991.

(ii) Within the next 100 CIS after the effective date of this AD or prior to accumulating 1,500 CIS since accomplishing the immersion ultrasonic inspection, in accordance with the Accomplishment Instructions, paragraph 2.B of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, whichever occurs later, for those disks which on the effective date of this AD have accumulated less than 1,500 CIS since accomplishing the immersion ultrasonic inspection in accordance with the Accomplishment Instructions, paragraph 2.B. of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991.

(c) Thereafter, eddy current inspect the bore forward corner of stage 1 fan disks which meet the acceptance criteria of paragraph 2.A.(2)(c) of the Accomplishment Instructions of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, at intervals not to exceed 500 CIS since last eddy current inspection.

(d) Remove from service prior to further flight and replace with a serviceable part, disks inspected in accordance with paragraphs (b) and (c) of this AD, which do not meet the acceptance criteria of paragraph 2.A.(2)(c) of the Accomplishment Instructions of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991.

(e) Remove from service and replace with a serviceable part all Group B stage 1 fan disks at the next shop visit but no later than 2,500 CIS since immersion ultrasonic inspection in accordance with the AccomplishmentInstructions, paragraph 2.B. of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, or June 30, 1992, whichever occurs first.

(f) Immersion ultrasonic inspect in accordance with the Accomplishment Instructions, paragraph 2.B. of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991, at the next engine shop visit or no later than December 31, 1991, whichever occurs first, stage 1 fan disks identified by S/N in Group C, Figure 3 of GE SB 72-962, Revision 3, dated May 22, 1991.

(g) For the purpose of this AD, "shop visit" is defined as the induction of the engine into the shop for any reason.

(h) Stage 1 fan disks that have been inspected to the Immersion Ultrasonic Inspection of CF6-6 Commercial Engine Service Memorandum (CESM) No. 98, have been found serviceable and comply with the immersion ultrasonic requirements of this AD.

(i) Remove from service prior to further flight those disks inspected in accordance with paragraph (f) of this AD which do not meet the acceptance criteria of paragraph 2.B. of the Accomplishment Instructions of GE CF6-6 SB 72-962, Revision 3, dated May 22, 1991.

(j) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.

(k) Upon submission of substantiating data by an owner or operator through an FAA Inspector, (maintenance, avionics, or operations, as appropriate) an alternate method of compliance with the requirements of this AD or adjustments to the compliance schedules specified in this AD may be approved by the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 12 New England Executive Park, Burlington, Massachusetts 01803-5299.

The inspections and removal of fan disks shall be done in accordance with the following General Electric service documents:

Document No.
Page No.
Issue
Date
CF6-6 S/B 72-962
1 and 13
Rev. 3
May 22, 1991

2 thru 4
Rev. 2
Feb. 8, 19918, 12, and 14

6, 9, 10
Rev. 1
Dec. 20, 1990

5, 7, and 11
original
July 2, 1990
Total Pages: 14

CF6-6 CESM No. 98
1 thru 3
Rev. 2
Oct. 5, 1989
Total Pages: 3

This incorporation was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to General Electric Company, Technical Publications Department, 1 Neumann Way, Cincinnati, Ohio 45215. This information may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, Room 311, 12 New England Executive Park, Burlington, Massachusetts, or at the Office of the Federal Register, 1100 L Street, NW, Room 8401, Washington, D.C.

This amendment (39-7066, AD 91-15-03) becomes effective on August 5, 1991.