AD 90-23-15 ACTIVE

90-23-15 GENERAL ELECTRIC COMPANY: Amendment 39-6754. Docket No. 89-ANE-06.
Applicability: General Electric Company (GE) CF6-50/-45 series turbofan engines installed on, but not limited to, McDonnell-Douglas DC-10, Boeing 747, and Airbus A300 type aircraft.
Compliance: Required as indicated, unless previously accomplished.
To prevent turbine mid-frame (TMF) cracks which can cause the release of hot gas, increased nacelle temperature, activation of the fire warning system, and an inflight shutdown, accomplish the following:
(a) Inspect the TMF, Part Numbers (P/N) 9128M52 and 9137M92 that do not incorporate GE CF6-50/- 45 Service Bulletin (SB) 72-973 or 72-975, in accordance with GE CF6-50/-45 SB 72-957, Revision 2, dated January 9, 1990, as follows:
(1) Inspect TMF cases with 1,050 or greater cycles since new (CSN) on the effective date of this AD, at the next shop visit or prior to accumulating the next 450 cycles in service (CIS) after the effective date of this AD, whichever occurs first.
(2) Inspect TMF cases with less than 1,050 CSN on the effective date of this AD, prior to accumulating 1,500 CSN.
(3) Remove from service, prior to further flight, TMF cases which exceed the serviceable limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(4) Thereafter, for TMF cases used in CF6-50 engines, reinspect cases with no cracks or indications at intervals not to exceed 600 CIS since previous inspection. Reinspect TMF cases with cracks or indications in accordance with the schedules and limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(5) Thereafter, for TMF cases used exclusively in CF6-45 engines, reinspect cases with no cracks or indications at intervals not to exceed 750 CIS since previous inspection. Reinspect TMF cases with cracks or indications in accordance with the schedules and limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(b) Inspect the TMF, P/N 9128M52 and 9137M92 that incorporate GE CF6-50/-45 SB 72-973, Revision 1, dated April 20, 1990, in accordance with GE CF6-50/-45 SB 72-957, Revision 2, dated January 9, 1990, as follows:
(1) Inspect TMF cases prior to accumulating 6,000 CIS since incorporation of GE SB 72-973, Revision 1, dated April 20, 1990.
(2) Remove from service, prior to further flight, TMF cases which exceed the serviceable limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(3) Thereafter, for CF6-50/-45 engines, reinspect TMF cases with no cracks or indications at each engine shop visit, not to exceed 2,400 CIS since last inspection. Reinspect TMF cases with cracks or indications, in accordance with the schedules and limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(c) Inspect the TMF, P/N 9128M52 and 9137M92 that incorporate GE CF6-50/-45 SB 72-975, dated December 11, 1989, in accordance with GE CF6-50/-45 SB 72-957, Revision 2, dated January 9, 1990, as follows:
(1) For TMF cases used in CF6-50 engines, inspect cases prior to accumulating 1,200 CIS since incorporation of GE SB 72-975, dated December 11, 1989. Thereafter, reinspect TMF cases with no cracks or indications at each engine shop visit, not to exceed 1,200 CIS since last inspection.
(2) For TMF cases used exclusively in CF6-45 engines, inspect cases prior to accumulating 1,500 CIS since incorporation of GE SB 72-975, dated December 11, 1989. Thereafter, reinspect TMF cases with no cracks or indications at each engine shop visit, not to exceed 1,500 CIS since last inspection.
(3) Remove from service, prior to further flight, TMF cases which exceed the serviceable limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(4) For CF6-50/-45 engines, reinspect TMF cases with cracks or indication in accordance with the schedules and limits specified in Tables 1-4 inclusive of GE SB 72-957, Revision 2, dated January 9, 1990.
(d) Inspections previously performed in accordance with AD 90-06-07, are considered to be in compliance with the corresponding requirements of this AD.
(e) For the purpose of this AD, shop visit is defined as the introduction of an engine into a shop for the conduct of engine maintenance.
(f) For the purpose of this AD, applicable limits are those limits associated with the highest engine rating under which the TMF case has operated.
(g) 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.
(h) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this AD or adjustments to the compliance schedule specified in this AD may be approved by the Manager, Engine Certification Office, ANE-140, Engineand Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803.
The initial and repetitive inspection program shall be done in accordance with the following GE documents:

DOCUMENT
PAGE
REVISION
DATE
GE SB 72-957
All
2
Jan. 9, 1990
GE SB 72-973
All
1
April 20, 1990
GE SB 72-975
All
Original
Dec. 11, 1990

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from the General Electric Company, Technical Publications Department, 1 Neumann Way, Cincinnati, Ohio 45215. Copies may be inspected at the Regional Rules Docket, Office of the Assistant Chief Counsel, New England Region, 12 New England Executive Park, Room 311, Burlington, Massachusetts 01803, or at the office of the Federal Register, 1100 L Street, NW, Room 8301, Washington, D.C.20591.
Airworthiness Directive 90-23-15 supersedes AD 90-06-07, Amendment 39-6449.
This amendment (39-6754, AD 90-23-15) becomes effective on December 6, 1990.