AD 91-07-17

91-07-17 GENERAL ELECTRIC COMPANY: Amendment 39-6954. Docket No. 90-ANE-23. Applicability: General Electric Company (GE) CT58-140-1 turboshaft engines overhauled by H&S Aviation, Division 3 (Formerly Hants and Sussex), Portsmouth, England, between March 14, 1989, and August 21, 1989, installed on, but not limited to, Sikorsky S-61 and Boeing V107 aircraft. The affected parts are identified by part number (P/N) and serial number (S/N) and are installed in engines with S/N, as follows:

Engine S/N Part Name P/N Part S/N 295235 Stage 1 forward cooling plate 37C30005P101 BJWTMS 7732

Stage 1 aft cooling plate 3002T25P01 BJWTMS 6649

Stage 2 forward cooling plate 000T88P02 ASVA 3663

Stage 2 aft cooling plate 3002T27P01 ASVA 0125

Power Turbine (PT) wheel & shaft 5002T30P01 GAT 59510 295206 Stage 1 turbine wheel 4002T17P02 GATBK 483

Stage 2 turbine wheel 4002T96P02 GATFE 352 280326 Stage 2 turbine wheel 4002T96P02 GATL 2835

PT wheel and shaft 5002T30P01 GAT 59722 280218 PT wheel and shaft 5002T30P01 GAT 59692 280294 Stage 1 forward cooling plate 37C300055P101 BJWTMS 7663

Stage 1 aft cooling plate 3002T25P01 5778 5778

Stage 2 forward cooling plate 3000T88P02 BJWTMS 5951

Stage 2 aft cooling plate 3002T27P01 BJWTMS 7356

Stage 2 turbine wheel 4002T96P02 GATEL 092

Compliance: Required as indicated, unless already accomplished. To prevent failure of suspect gas generator (GG) turbine rotor parts and power turbine (PT) wheels, which may have a reduced low cycle fatigue life due to inadvertent shotpeening which could result in an uncontained engine failure, remove and inspect all surfaces of GG turbine rotor parts and PT wheels identified above by 20x microscope as follows: (a) Part S/N BJWTMS 7732, BJWTMS 6649, ASVA 3663, ASVA 0125, and GAT 59510, prior to accumulating 5,853 cycles since new (CSN). (b) Part S/N GATBK 483, and GATFE 352, prior to accumulating 5,249 CSN. (c) Part S/N GATL 2835, prior to accumulating 10,792 CSN. (d) Part S/N GAT 59722, prior to accumulating 10,856 CSN. (e) Part S/N GAT 59692, prior to accumulating 9,660 CSN. (f) Part S/N BJWTMS 7663, BJWTMS 5778, BJWTMS 5951, BJWTMS 7356, and GATEL 092, prior to accumulating 5,696 CSN. (g) Remove from service parts found with evidence of shotpeening and replace with a serviceable part. Reidentify parts found with no evidence of shotpeening prior to return to service. NOTE: GE Alert Service Bulletin CT58 A72-173 (CEB-275), contains information in reference to paragraphs (a) through (g) above. (h) 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. (i) 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, Engine and Propeller Directorate, Aircraft Certification Service, FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803-5299. All persons affected by this directive who have not already received the appropriate alert service bulletin from the manufacturer may obtain copies upon request to GE Aircraft Engines, 1000 Western Avenue, Lynn, Massachusetts 01910. These documents may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, Room 311, 12 New England Executive Park, Burlington, Massachusetts. This amendment (39-6954, AD 91-07-17) becomes effective on April 26, 1991.