84-24-54 R2 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. (ALLISON, formerly DETROIT DIESEL ALLISON): Amendment 39-5163 as amended by Amendment 39-5192. Applies to Allison Model 250-C30 Series engines installed in rotorcraft certificated in any category with the following engine and turbine serial numbers:
MODEL
ENGINE SERIAL NUMBER
TURBINE SERIAL NUMBER
250-C30
CAE 900001 thru 9000026
CAT 900001 thru 90683, 95001 thru 95336, 95338 thru 95347, 95349, 95350, 95352 thru 95365, 95368, 95370, 95372 thru 95374, 95376 thru 95394, 95396, 95398 thru 95407
250-C30, -C30S
CAE 890001 thru 890840,
890843 thru 890847,
890849 thru 890858,
890860, 890861, 890863
Same as above.
250-C30R
CAE 895068, 895077,
895078, 895082, 895084,
895085, 895096
Same as above.
250-C30P
CAE 895001 thru 895177
Same as above.
EXCEPT: Existing Model 250-C30 Series engines which have incorporated all of the following Allison Commercial Engine Bulletins (CEB's):SUBJECT
CEB-A-72-3134, Rev. 2 dated Sept. 15, 1985, or CEB-A-72-3135, Rev. 1 dated Sept. 15, 1985, or FAA approved equivalents; and
Engine, Turbine Assembly, Turbine-to-Compressor Coupling Shaft-Replace
CEB-72-3100, Rev. 1 dated Sept. 15, 1985, or FAA approved equivalent; and
Engine, Compressor Assembly, Spur Adapter Gearshaft - modified by adding Three Slots in Bore & Plugging Oil Feed Hole
CEB-72-3059, Rev. 4 dated
Sept. 15, 1985, or FAA approved
equivalent; and
Engine, Compressor and Gearbox Assemblies - modify to Roller Number 2 1/2 Bearing Configuration
CEB-72-3096, Rev. 1 dated Sept. 15, 1985, or FAA approved equivalent.
Engine, Turbine-Exhaust Collector Modifications
Compliance is required as indicated unless already accomplished.
To prevent possible cracks in turbine-to-compressor coupling P/N 23008080, or carbon buildup on turbine shafts and couplings that can cause shaft rub, or shafting misalignment from progressing to where a disconnect failure could occur and subsequently could result in an overspeed uncontained failure of the gas producer turbine rotor, accomplish the following:
(a) Model 250-C30 and -C30S engines installed in Sikorsky S-76A rotorcraft
(1) Before further flight, remove P/N 23008080 coupling and replace with P/N 23032345 in accordance with Allison CEB-A-72-3134, Revision 2 dated September 15, 1985, or FAA approved equivalent; or, as alternative temporary compliance, until next turbine repair/overhaul shop visit, but not later than November 30, 1986, replace P/N 23008080 coupling with serviceable P/N 6896895, or P/N 6889071, in accordance with Allison CEB-A-72-3134, Revision 2 dated September 15, 1985, or FAA approved equivalent.
(2) Within the next 50 hours time-in-service after the effective date of this AD, unless already accomplished within the last 250 hours time-in-service, and thereafter at intervals not to exceed 300 hours time- in-service from the last inspection, perform the following:
Inspect, clean turbine shafting/couplings, and replace the P/N AS 3085-018 O-ring (two for P/N 23032345 and one for P/N 6896895 or P/N 6889071) on the aft end of the spur adapter gearshaft in accordance with CEB-A-72-3108, Revision 3 dated September 15, 1985, or FAA approved equivalent.
(3) At the next engine repair/overhaul shop visit, when both the compressor and gearbox are disassembled to permit access, but not later than November 30, 1986, perform the following:
(i) Modify spur adapter gearshaft assembly P/N 23005276 in accordance with Allison CEB 72-3100, Revision 1 dated September 15, 1985, or FAA approved equivalent.
(ii) Modify engine compressor and gearbox assemblies to include the roller bearing configuration at the 2 1/2 bearing location in accordance with Allison CEB 72-3059, Revision 4 dated September 15, 1985, or FAA approved equivalent.
(iii) Replace turbine-to-compressor-coupling, P/N 6896895, or P/N 6889071, with P/N 23032345 and install twoP/N AS 3085-018 O-rings on the aft end of the spur adapter gearshaft in accordance with Allison CEB-A-72-3134, Revision 2 dated September 15, 1985, or FAA approved equivalent.
(4) At the next turbine repair/overhaul shop visit, but not later than November 30, 1986, modify the turbine-exhaust-collector in accordance with Allison CEB 72-3096, Revision 1 dated September 15, 1985, or FAA approved equivalent.
(b) Model 250-C30, -C30P, -C30R and -C30S engines installed in other than Sikorsky S-76A rotorcraft
(1) Within the next 50 hours time-in-service after the effective date of this AD, unless already accomplished within the last 250 hours time-in-service, and thereafter at intervals not to exceed 300 hours time- in-service from the last inspection, perform the following:
Inspect, clean turbine shafting/couplings, and replace the P/N AS 3085-018 O-ring (two for P/N 23032345 and one for P/N 6896895 or P/N 6889071) on the aft end of the spur adapter gearshaft in accordance with CEB-A-72-3143 dated September 15, 1985, or FAA approved equivalent.
(2) Within the next 300 hours time in service after November 18, 1985, or within 100 hours time in service after the effective date of this amendment, or at next turbine repair/overhaul shop visit, whichever occurs first, but not later than March 6, 1986, perform the following:
Replace turbine-to-compressor coupling P/N 23008080 with P/N 23032345 and install two P/N AS 3085-018 O-rings on the aft end of the spur adapter gearshaft in accordance with Allison CEB-A-72- 3135, Revision 1 dated September 15, 1985, or FAA approved equivalent.
(3) At the next engine repair/overhaul shop visit when both the compressor and gearbox are disassembled to permit access, but not later than November 30, 1987, perform the following:
(i) Modify spur adapter gearshaft assembly P/N 23005276 in accordance with Allison CEB 72-3100, Revision 1 dated September 15, 1985, or FAA approved equivalent.
(ii) Modify engine compressor and gearbox assemblies to include the roller bearing configuration at the 2 1/2 bearing location in accordance with Allison CEB 72-3059, Revision 4 dated September 15, 1985, or FAA approved equivalent.
(iii) Replace turbine-to-compressor-coupling P/N 6896895, or P/N 6889071, with P/N 23032345 and install two P/N AS 3085-018 O-rings on the aft end of the spur adapter gearshaft in accordance with Allison CEB-A-72-3135, Revision 1 dated September 15, 1985, or FAA approved equivalent.
(4) At the next turbine repair/overhaul shop visit, but not later than November 30, 1987, modify the turbine-exhaust-collector in accordance with Allison CEB 72-3096, Revision 1 dated September 15, 1985, or FAA approved equivalent.
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.
Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Chicago AircraftCertification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018.
Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Chicago Aircraft Certification Office may adjust the compliance time specified in this AD.
The following Allison Commercial Engine Bulletins are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1):
CEB-A-72-3134, Revision 2 dated September 15, 1985
CEB-A-72-3135, Revision 1 dated September 15, 1985
CEB-72-3100, Revision 1 dated September 15, 1985
CEB-72-3059, Revision 4 dated September 15, 1985
CEB-A-72-3108, Revision 3 dated September 15, 1985
CEB-72-3096, Revision 1 dated September 15, 1985
CEB-A-72-3143 dated September 15, 1985
All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Allison Gas Turbine Division, General Motors Corp., P.O. Box 420, Indianapolis, IN 46206-0420. These documents also may be examined at the Office of Regional Counsel, FAA, ATTN: Rules Docket No. 84-ANE-29, 12 New England Executive Park, Burlington, Massachusetts 01803, weekdays, except Federal holidays, between 8:00 a.m. and 4:30 p.m.
This amendment supersedes Amendment 39-4755, 48 FR 51287, AD 83-22-05.
Amendment 39-5163 became effective November 18, 1985, to all persons except those persons to whom it was made immediately effective by telegraphic AD T84-24-54, issued December 10, 1984, which contained this amendment.
This Amendment 39-5192 becomes effective January 6, 1986