AD 86-20-13

final rule

ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines

AD Number
86-20-13
Status
final_rule
Effective Date
Product Category
engine
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
engine Rolls-Royce Corporation 250-C28B ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C28C ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30G ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30G/2 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30M ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30P ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30R (T703-AD-700) ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30R/1 (T703-AD-700B) ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30R/3 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30S ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
engine Rolls-Royce Corporation 250-C30U ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines

Unsafe Condition

Excessive wear and/or fretting damage on the external splines of the turbine spline adapter or the aft splines of the turbine-to-compressor coupling shaft can progress to a disconnect and subsequent overspeed gas generator turbine failure/uncontained failure.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Within five hours time-in-service after the effective date, but not later than December 20, 1986, inspect the gas generator turbine spline adapter locknut torque. For uninstalled affected turbine assemblies, inspect the locknut torque before initial flight.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within the next five hours time-in-service after the effective date of this AD, but not later than December 20, 1986, for in-service engines. Before initial flight, for uninstalled affected turbine assemblies.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Allison Model 250-C28B, 250-C28C, and 250-C30 Series engines with turbine serial numbers CAT 70001 thru 70802 and 70804 (C28B), CAT 28001 thru 28046 (C28C), and CAT 90001 thru 95436 and 95438 (C30 Series), except those incorporating specified Allison Commercial Engine Alert Bulletin or FAA approved equivalents.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

External Splines

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_86-20-13.html
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AD Number:
86-20-13
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
Subject:
External Splines
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/03/1986
Make:
Rolls-Royce Corporation
Model:
250-C28B | 250-C28C | 250-C30 | 250-C30G | 250-C30G/2 | 250-C30M | 250-C30P | 250-C30R (T703-AD-700)...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 86-20-13
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-5465

AD NUMBER:   86-20-13

SUBJECT HEADING:   ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines

ACTION:  

SUMMARY:  

DATES:   Effective December 3, 1986.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   86-20-13 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. (ALLISON, formerly DETROIT DIESEL ALLISON): Amendment 39-5465. Applies to Allison Model 250-C28 and -C30 Series engines installed in, but not limited to, Bell Model 206L-1, Messerschmitt-Bolkow-Blohm GmbH BO 105 LS A- 1, Sikorsky Model S-76A, Bell Model 206L-1, modified to incorporate the Allison 250-C30 engine, Bell Model 206L-3, and McDonnell Douglas Helicopter Company (Hughes) Model 369F and 369FF aircraft.
The following engine models and turbine serial numbers are affected:


ENGINE MODEL	TURBINE SERIAL NUMBER
250-C28B	CAT 70001 thru 70802 and 70804
250-C28C	CAT 28001 thru 28046
250-C30 Series	CAT 90001 thru 95436 and 95438

EXCEPT existing Model 250-C28 and 250-C30 Series engines which have incorporated Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, or the following FAA approved equivalents:

Allison Message THO-2639W-RFR-85 dated February 7, 1985
Allison C28 Overhaul Manual Temporary Revision 72-7, Page 12 dated January 22, 1986
Allison C30 Overhaul Manual Revision dated July 1, 1985, Section 72-50-00, Paragraph (7), page 524
Allison Commercial Service Letter 250-C28/C30 CSL-2071/3073 dated June 1, 1985

Compliance is required as indicated unless already accomplished.
To prevent excessive wear and/or fretting damage on the external splines of the turbine spline adapter or the aft splines of the turbine-to-compressor coupling shaft, which can progress to a disconnect and subsequent overspeed gas generator turbine failure/uncontained failure, accomplish the following:
(a) Within the next five hours time-in-service after the effective date of this AD, but not later than December 20, 1986, for inservice engines, inspect the gas generator turbine spline adapter locknut torque in accordance with Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, or FAA approved equivalent.
(b) Before initial flight, for uninstalled affected turbine assemblies, inspect the gas generator turbine spline adapter locknut torque in accordance with Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB- A-72-2132/3146 dated October 1, 1985, or FAA approved equivalent.
NOTE: The compliance requirements of this AD were previously published in Allison Commercial Service Letter 250-C28/C30 CSL-A-2084/3087, Revision 1, dated September 29, 1986, FAA approved by the Manager, Chicago Aircraft Certification Office.
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 Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018.
Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552 (a)(1). All persons affected by this directive who have not already received this document from the manufacturer may obtain copies upon request to Allison Gas Turbine Division, General Motors Corp., P.O. Box 420, Indianapolis, Indiana 46206-0420. This document also may be examined at the Office of Regional Counsel, FAA, ATTN: Rules Docket No. 86-ANE-41, 12 New England Executive Park, Burlington, Massachusetts 01803, weekdays, except Federal holidays, between 8:00 a.m. and 4:30 p.m.
This amendment becomes effective December 3, 1986, as to all persons except those persons to whom it was made immediately effective by Priority Letter AD No. 86-20-13, issued October 8, 1986, which contained this amendment.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_86-20-13.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
86-20-13
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines
Subject:
External Splines
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/03/1986
Make:
Rolls-Royce Corporation
Model:
250-C28B | 250-C28C | 250-C30 | 250-C30G | 250-C30G/2 | 250-C30M | 250-C30P | 250-C30R (T703-AD-700)...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 86-20-13
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-5465

AD NUMBER:   86-20-13

SUBJECT HEADING:   ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines

ACTION:  

SUMMARY:  

DATES:   Effective December 3, 1986.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   86-20-13 ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. (ALLISON, formerly DETROIT DIESEL ALLISON): Amendment 39-5465. Applies to Allison Model 250-C28 and -C30 Series engines installed in, but not limited to, Bell Model 206L-1, Messerschmitt-Bolkow-Blohm GmbH BO 105 LS A- 1, Sikorsky Model S-76A, Bell Model 206L-1, modified to incorporate the Allison 250-C30 engine, Bell Model 206L-3, and McDonnell Douglas Helicopter Company (Hughes) Model 369F and 369FF aircraft.
The following engine models and turbine serial numbers are affected:


ENGINE MODEL	TURBINE SERIAL NUMBER
250-C28B	CAT 70001 thru 70802 and 70804
250-C28C	CAT 28001 thru 28046
250-C30 Series	CAT 90001 thru 95436 and 95438

EXCEPT existing Model 250-C28 and 250-C30 Series engines which have incorporated Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, or the following FAA approved equivalents:

Allison Message THO-2639W-RFR-85 dated February 7, 1985
Allison C28 Overhaul Manual Temporary Revision 72-7, Page 12 dated January 22, 1986
Allison C30 Overhaul Manual Revision dated July 1, 1985, Section 72-50-00, Paragraph (7), page 524
Allison Commercial Service Letter 250-C28/C30 CSL-2071/3073 dated June 1, 1985

Compliance is required as indicated unless already accomplished.
To prevent excessive wear and/or fretting damage on the external splines of the turbine spline adapter or the aft splines of the turbine-to-compressor coupling shaft, which can progress to a disconnect and subsequent overspeed gas generator turbine failure/uncontained failure, accomplish the following:
(a) Within the next five hours time-in-service after the effective date of this AD, but not later than December 20, 1986, for inservice engines, inspect the gas generator turbine spline adapter locknut torque in accordance with Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, or FAA approved equivalent.
(b) Before initial flight, for uninstalled affected turbine assemblies, inspect the gas generator turbine spline adapter locknut torque in accordance with Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB- A-72-2132/3146 dated October 1, 1985, or FAA approved equivalent.
NOTE: The compliance requirements of this AD were previously published in Allison Commercial Service Letter 250-C28/C30 CSL-A-2084/3087, Revision 1, dated September 29, 1986, FAA approved by the Manager, Chicago Aircraft Certification Office.
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 Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018.
Allison Commercial Engine Alert Bulletin 250-C28/C30 CEB-A-72-2132/3146 dated October 1, 1985, is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552 (a)(1). All persons affected by this directive who have not already received this document from the manufacturer may obtain copies upon request to Allison Gas Turbine Division, General Motors Corp., P.O. Box 420, Indianapolis, Indiana 46206-0420. This document also may be examined at the Office of Regional Counsel, FAA, ATTN: Rules Docket No. 86-ANE-41, 12 New England Executive Park, Burlington, Massachusetts 01803, weekdays, except Federal holidays, between 8:00 a.m. and 4:30 p.m.
This amendment becomes effective December 3, 1986, as to all persons except those persons to whom it was made immediately effective by Priority Letter AD No. 86-20-13, issued October 8, 1986, which contained this amendment.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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