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.