AD 85-25-56 R1
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | General Electric Company | CF6-45A | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-45A2 | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50A | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50C | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50C1 | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50C2 | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50C2B | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50C2D | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50CA | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50E | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50E1 | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50E2 | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
| engine | General Electric Company | CF6-50E2B | GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines |
Unsafe Condition
Failure of the left hand side seventh stage low pressure turbine (LPT) cooling air manifold tube could result in an LPT overtemperature condition and subsequent LPT stage 1 disk rupture.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Accomplish requirements of GE SB 75-55 paragraphs 2.A.1., 2.A.2., and 2.A. with FAA approved equivalents within 10 flight cycles. Then accomplish paragraph 2 of GE SB 75-55 within 60 calendar days. For engines already compliant with SB 75-54 or SB 75-46, accomplish paragraph 2 of SB 75-55 within 60 days. Replace cracked hardware before flight. Inspect tubes and hardware every 250 flight cycles. Replace or tighten worn hardware before flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 10 flight cycles after the effective date for initial actions, and within 60 calendar days for subsequent steps. Inspections required within the next 250 flight cycles and recurring every 250 flight cycles.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
General Electric Company CF6-45A, CF6-45A2, CF6-50A, CF6-50C, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2D, CF6-50CA, and other CF6-50 and -45 series engines as listed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Seventh Stage Low Pressure Turbine (LPT) Cooling Air Manifold Tube
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_85-25-56_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 85-25-56 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines Subject: Seventh Stage Low Pressure Turbine (LPT) Cooling Air Manifold Tube Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: General Electric Company Model: CF6-45A | CF6-45A2 | CF6-50A | CF6-50C | CF6-50C1 | CF6-50C2 | CF6-50C2B | CF6-50C2D | CF6-50CA | CF...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: AIRWORTHINESS DIRECTIVES FINAL RULES: 85-25-56 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5495 AD NUMBER: 85-25-56 R1 SUBJECT HEADING: GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 85-25-56 R1 GENERAL ELECTRIC COMPANY: Telegram issued December 20, 1985, as amended by Amendment 39-5495. Applies to General Electric Company (GE) CF6-50 and -45 series turbofan engines. Compliance is required as indicated, unless already accomplished. To prevent failure of the left hand side seventh stage low pressure turbine (LPT) cooling air manifold tube, which could result in an LPT overtemperature condition and subsequent LPT stage 1 disk rupture, accomplish the following: (a) For those engines not in compliance with the requirements of GE Service Bulletin (SB) 75-54, dated July 19, 1985, or paragraph 2.A. or 2.B. of GE SB 75-46, Revision 3, dated June 8, 1982, comply with paragraphs (1) then (2) below: (1) Accomplish the requirements of paragraphs 2.A.1. and 2.A.2. of GE SB 75-55, dated September 13, 1985, concurrently with the requirements of paragraph 2.A. of GE SB 75-54, or FAA approved equivalents, within 10 flight cycles after the effective date of this AD. (2) Accomplish the requirements of paragraph 2. of GE SB 75-55 or FAA approved equivalent, within 60 calendar days of complying with paragraph (1) above. (b) For engines already in compliance with the requirements of GE SB 75-54 or paragraph 2.A. or 2.B. of GE SB 75-46, accomplish the requirements of paragraph 2. of GE SB 75-55 within 60 calendar days after the effective date of this AD. (c) Replace cracked, broken or ruptured left hand side seventh stage LPT cooling air manifold tube and attachment hardware, found during accomplishment of paragraph (a) or (b) above, before further flight. (d) Inspect the left hand side seventh stage LPT cooling air manifold tubes and attachment hardware in accordance with the requirements of paragraphs 2.A., 2.B., 2.C. and 2.D.(4)(b) of GE SB 75-58, dated April 14, 1986, or FAA approved equivalent, within the next 250 flight cycles after the effective date of this AD, and thereafter, at intervals not to exceed 250 flight cycles from the last inspection. (e) Replace or tighten, in accordance with paragraph 2.D. of GE SB 75-58, left hand side seventh stage LPT cooling air system hardware found worn, loose, cracked or broken during accomplishment of paragraph (d) above, prior to further flight. 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, Engine Certification Office, Aircraft Certification Division, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Engine Certification Office, may adjust the compliance time specified in this AD. GE SB's 75-54, dated July 19, 1985; 75-46, Revision 3, dated June 8, 1982; 75-55, dated September 13, 1985; and 75-58, dated April 14, 1986, identified and described in this document, are 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 these documents from the manufacturer may obtain copies, upon request, from General Electric Company, 1 Neumann Way, Cincinnati, Ohio 45215. These documents also may be examined at the Office of the Regional Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, Rules Docket Number 85-ANE-44, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Paragraphs (a), (b), and (c) of this amendment become effective January 5, 1987, as to all persons except those persons to whom paragraphs (a), (b), and (c) of this amendment were made immediately effective by TAD T85-25-56, issued December 20, 1985. Paragraphs (d) and (e) of this amendment become effective January 13, 1987, as to all persons. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_85-25-56_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 85-25-56 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines Subject: Seventh Stage Low Pressure Turbine (LPT) Cooling Air Manifold Tube Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: General Electric Company Model: CF6-45A | CF6-45A2 | CF6-50A | CF6-50C | CF6-50C1 | CF6-50C2 | CF6-50C2B | CF6-50C2D | CF6-50CA | CF...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: AIRWORTHINESS DIRECTIVES FINAL RULES: 85-25-56 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5495 AD NUMBER: 85-25-56 R1 SUBJECT HEADING: GENERAL ELECTRIC COMPANY Models CF6-50 and -45 Series Engines ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 85-25-56 R1 GENERAL ELECTRIC COMPANY: Telegram issued December 20, 1985, as amended by Amendment 39-5495. Applies to General Electric Company (GE) CF6-50 and -45 series turbofan engines. Compliance is required as indicated, unless already accomplished. To prevent failure of the left hand side seventh stage low pressure turbine (LPT) cooling air manifold tube, which could result in an LPT overtemperature condition and subsequent LPT stage 1 disk rupture, accomplish the following: (a) For those engines not in compliance with the requirements of GE Service Bulletin (SB) 75-54, dated July 19, 1985, or paragraph 2.A. or 2.B. of GE SB 75-46, Revision 3, dated June 8, 1982, comply with paragraphs (1) then (2) below: (1) Accomplish the requirements of paragraphs 2.A.1. and 2.A.2. of GE SB 75-55, dated September 13, 1985, concurrently with the requirements of paragraph 2.A. of GE SB 75-54, or FAA approved equivalents, within 10 flight cycles after the effective date of this AD. (2) Accomplish the requirements of paragraph 2. of GE SB 75-55 or FAA approved equivalent, within 60 calendar days of complying with paragraph (1) above. (b) For engines already in compliance with the requirements of GE SB 75-54 or paragraph 2.A. or 2.B. of GE SB 75-46, accomplish the requirements of paragraph 2. of GE SB 75-55 within 60 calendar days after the effective date of this AD. (c) Replace cracked, broken or ruptured left hand side seventh stage LPT cooling air manifold tube and attachment hardware, found during accomplishment of paragraph (a) or (b) above, before further flight. (d) Inspect the left hand side seventh stage LPT cooling air manifold tubes and attachment hardware in accordance with the requirements of paragraphs 2.A., 2.B., 2.C. and 2.D.(4)(b) of GE SB 75-58, dated April 14, 1986, or FAA approved equivalent, within the next 250 flight cycles after the effective date of this AD, and thereafter, at intervals not to exceed 250 flight cycles from the last inspection. (e) Replace or tighten, in accordance with paragraph 2.D. of GE SB 75-58, left hand side seventh stage LPT cooling air system hardware found worn, loose, cracked or broken during accomplishment of paragraph (d) above, prior to further flight. 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, Engine Certification Office, Aircraft Certification Division, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Engine Certification Office, may adjust the compliance time specified in this AD. GE SB's 75-54, dated July 19, 1985; 75-46, Revision 3, dated June 8, 1982; 75-55, dated September 13, 1985; and 75-58, dated April 14, 1986, identified and described in this document, are 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 these documents from the manufacturer may obtain copies, upon request, from General Electric Company, 1 Neumann Way, Cincinnati, Ohio 45215. These documents also may be examined at the Office of the Regional Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, Rules Docket Number 85-ANE-44, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Paragraphs (a), (b), and (c) of this amendment become effective January 5, 1987, as to all persons except those persons to whom paragraphs (a), (b), and (c) of this amendment were made immediately effective by TAD T85-25-56, issued December 20, 1985. Paragraphs (d) and (e) of this amendment become effective January 13, 1987, as to all persons. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2023-04-11
final ruleAirworthiness Directives; General Electric Company Turbofan Engines
Unsafe Condition: Separation of the low-pressure turbine (LPT) rotor assembly, resulting in the LPT rotor assembly departing the rear of the engine.
2011-23-04 Recurring
final ruleAirworthiness Directives; General Electric Company (GE) CF6 Turbofan Engines
Unsafe Condition: Failure of the side links and possible engine separation from the airplane.
2011-07-01
final ruleAirworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines
Unsafe Condition: The forward and aft centerbody of the LFCEN assembly may separate from the engine, causing damage to the engine, and damage to the airplane.
2007-19-06
final ruleAirworthiness Directives; General Electric Company Aircraft Engine Group (GEAE) CF6-45A Series, CF6-50A, CF6-50C Series and CF6-50E Series Turbofan Engines
Unsafe Condition: Reports of five events involving fractured compressor discharge pressure (CDP) restoring spring assembly, which could lead to loss of engine thrust control and loss of control of the airplane.