AD 88-07-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | General Electric Company | CT7-5A2 | GENERAL ELECTRIC Model CT7-5A, -5A1, and -5A2 Engines |
Unsafe Condition
Power turbine overspeed resulting in an uncontained failure or adverse aircraft yaw due to reaction of the fuel control to an erroneous PT speed signal during ground operation with the bottoming governor enabled.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove propeller overspeed governor (Dowty Rotol P/N 661001001) and replace with P/N 661001002 per DR SB SF340-61-11. Install cable GE P/N 6068T47P01 between OSG and hydromechanical unit per GE SB 74-09. Install engine BG deactivation switches (Saab Mod Kit SF340-76-018-01) per Saab SB SF340-76-018. Remove BG disabling procedures from AFM per AD 86-10-51 and discontinue those procedures. Ferrying allowed under FAR 21.197/199. Equivalent compliance may be approved.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
no later than May 16, 1988
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
General Electric CT7-5A, -5A1, and -5A2 engines installed in Saab-Fairchild SF340A aircraft
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Power Turbine Overspeed
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_88-07-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 88-07-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: GENERAL ELECTRIC Model CT7-5A, -5A1, and -5A2 Engines Subject: Power Turbine Overspeed Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/09/1988 Make: General Electric Company Model: CT7-5A2 Product Type: Engine Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 88-07-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5869 AD NUMBER: 88-07-08 SUBJECT HEADING: GENERAL ELECTRIC Model CT7-5A, -5A1, and -5A2 Engines ACTION: SUMMARY: DATES: Effective May 9, 1988. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 88-07-08 GENERAL ELECTRIC: Amendment 39-5869. Applies to General Electric (GE) CT7-5A, -5A1, and -5A2 turbopropeller engines as installed in Saab-Fairchild SF340A aircraft. Compliance is required as indicated, unless already accomplished. To prevent power turbine (PT) overspeed resulting in an uncontained failure or adverse aircraft yaw due to reaction of the fuel control to an erroneous PT speed signal during ground operation with the bottoming governor (BG) enabled, accomplish the following no later than May 16, 1988: (a) Remove propeller overspeed governor (OSG), Dowty Rotol (DR) Part Number (P/N) 661001001, and replace with OSG, DR P/N 661001002, in accordance with procedures contained in DR Service Bulletin (SB) SF340-61-11, dated October 8, 1986. (b) Install cable, GE P/N 6068T47P01, between the propeller OSG and the hydromechanical unit in accordance with GE CT7 Turboprop SB 74-09, dated October 10, 1986. (c) Install engine BG deactivation switches, Mod Kit Saab SF340-76-018-01, in the power lever quadrant in accordance with procedures contained in Saab SB SF340-76-018, dated October 24, 1986. (d) Upon accomplishment of paragraphs (a) through (c) above: (1) Remove from the SF340A Aircraft Flight Manual (AFM) the BG disabling procedures required by AD 86-10-51, paragraphs (a)(1) and (a)2. (2) Discontinue operating in accordance with the procedures listed in AD 86-10-51, paragraph (b). NOTE: Subsequent to compliance with this AD, aircraft operation shall be conducted in accordance with the latest AFM revision. (e) Aircraft may be ferried in accordance with the provisions of Federal Aviation Regulations (FAR) 21.197 and 21.199 to a base where the AD can be accomplished. (f) 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. (g) Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Engine Certification Office, New England Region, may adjust the compliance time specified in this AD. Dowty Rotol SB SF340-61-11, dated October 8, 1986; General Electric CT7 Turboprop SB 74-09, dated October 10, 1986; and Saab SB SF340-76-018, dated October 24, 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 to Dowty Rotol Limited, Cheltenham Road East, Gloucester, England GL2 9QH; General Electric Company, 1000 Western Avenue, Lynn, Massachusetts 01910; and Saab-Scania AB, S-581 88, Linkoping, Sweden. This document may also 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 86-ANE-21, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays. This amendment supersedes Amendment 39-5473 (51 FR 44439; December 9, 1986), AD 86-10-51. This amendment becomes effective on May 9, 1988. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_88-07-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 88-07-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: GENERAL ELECTRIC Model CT7-5A, -5A1, and -5A2 Engines Subject: Power Turbine Overspeed Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/09/1988 Make: General Electric Company Model: CT7-5A2 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: 88-07-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5869 AD NUMBER: 88-07-08 SUBJECT HEADING: GENERAL ELECTRIC Model CT7-5A, -5A1, and -5A2 Engines ACTION: SUMMARY: DATES: Effective May 9, 1988. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 88-07-08 GENERAL ELECTRIC: Amendment 39-5869. Applies to General Electric (GE) CT7-5A, -5A1, and -5A2 turbopropeller engines as installed in Saab-Fairchild SF340A aircraft. Compliance is required as indicated, unless already accomplished. To prevent power turbine (PT) overspeed resulting in an uncontained failure or adverse aircraft yaw due to reaction of the fuel control to an erroneous PT speed signal during ground operation with the bottoming governor (BG) enabled, accomplish the following no later than May 16, 1988: (a) Remove propeller overspeed governor (OSG), Dowty Rotol (DR) Part Number (P/N) 661001001, and replace with OSG, DR P/N 661001002, in accordance with procedures contained in DR Service Bulletin (SB) SF340-61-11, dated October 8, 1986. (b) Install cable, GE P/N 6068T47P01, between the propeller OSG and the hydromechanical unit in accordance with GE CT7 Turboprop SB 74-09, dated October 10, 1986. (c) Install engine BG deactivation switches, Mod Kit Saab SF340-76-018-01, in the power lever quadrant in accordance with procedures contained in Saab SB SF340-76-018, dated October 24, 1986. (d) Upon accomplishment of paragraphs (a) through (c) above: (1) Remove from the SF340A Aircraft Flight Manual (AFM) the BG disabling procedures required by AD 86-10-51, paragraphs (a)(1) and (a)2. (2) Discontinue operating in accordance with the procedures listed in AD 86-10-51, paragraph (b). NOTE: Subsequent to compliance with this AD, aircraft operation shall be conducted in accordance with the latest AFM revision. (e) Aircraft may be ferried in accordance with the provisions of Federal Aviation Regulations (FAR) 21.197 and 21.199 to a base where the AD can be accomplished. (f) 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. (g) Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, Engine Certification Office, New England Region, may adjust the compliance time specified in this AD. Dowty Rotol SB SF340-61-11, dated October 8, 1986; General Electric CT7 Turboprop SB 74-09, dated October 10, 1986; and Saab SB SF340-76-018, dated October 24, 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 to Dowty Rotol Limited, Cheltenham Road East, Gloucester, England GL2 9QH; General Electric Company, 1000 Western Avenue, Lynn, Massachusetts 01910; and Saab-Scania AB, S-581 88, Linkoping, Sweden. This document may also 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 86-ANE-21, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays. This amendment supersedes Amendment 39-5473 (51 FR 44439; December 9, 1986), AD 86-10-51. This amendment becomes effective on May 9, 1988. 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
2025-05-02
final ruleAirworthiness Directives; General Electric Company Engines
Unsafe Condition: The failure of the stage 1 turbine forward cooling plate and stage 2 turbine aft cooling plate, which could result in uncontained engine failure and damage to the airplane.
2023-21-07 Recurring
final ruleAirworthiness Directives; General Electric Company Engines
Unsafe Condition: The main propeller shaft failure on a GE Model CT7-9B engine, resulting in the loss of the propeller.
2007-08-01
final ruleAirworthiness Directives; General Electric Company CT7-5, -7, and -9 Series Turboprop Engines
Unsafe Condition: Separation of the stage 2 turbine aft cooling plate, resulting in uncontained engine failure and damage to the airplane.
2004-07-09
final ruleAirworthiness Directives; General Electric Aircraft Engines CT7 Series Turboprop Engines
Unsafe Condition: Propeller gearbox (PGB) equipped with certain gears that do not meet design specifications, leading to separation of left-hand and right-hand idler gears, which could result in uncontained PGB fail...