AD 69-25-08

final rule

LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines

AD Number
69-25-08
Status
final_rule
Effective Date
Product Category
engine
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
engine Lycoming Engines GO-435-C2A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-435-C2A2 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-A1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-B LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-B1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-B1B LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-B1C LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-B1D LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C1B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C1D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C2C6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C2D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C2E6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-C3A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-D1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-E1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F2A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F2D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F3A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F3B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F4A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F4B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-F6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G1B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G1D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G1H6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G1J6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G2D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GO-480-G2F6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-A1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-A1C6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-A2A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1C6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1E6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1F6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1G6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B1J6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B2C6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B2D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B2G6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines GSO-480-B2H6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGO-540-A1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGO-540-A1B LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGO-540-B1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGO-540-B1B LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGO-540-B1C LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1A6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1B6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1C6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1D6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1E6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1F6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-480-A1G6 LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-A1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-A1C LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-A1D LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-A1E LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-A1F LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-B1A LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
engine Lycoming Engines IGSO-540-B1C LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines

Unsafe Condition

Failure of the reduction gear assembly due to improper torque on the pinion cage attaching nut and insufficient oil slinger design.

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

Required Actions

Inspect torque on the reduction gearing pinion cage attaching nut. Depending on torque reading, either replace components and adjust torque to 400 ft.-lbs. or disassemble, inspect components, and replace oil slinger and housing. Replace spline nut with an approved hexagonal nut. Stamp suffix (-1) on reduction gear housing if oil slinger P/N 77454 is used.

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

Compliance Time

Prior to the accumulation of 600 hours in service or 100 hours after the effective date of this AD whichever comes later for GO-435, IGO-540, and IGSO-540 engines; and prior to the accumulation of 700 hours in service or 100 hours after the effective date of this AD whichever comes later for GO-480, GSO-480, and IGSO-480 engines.

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

Affected Aircraft

Lycoming Engines models GO-435-C2A, GO-480, GSO-480, IGSO-480, IGO-540, and IGSO-540 type engines using specific reduction gear assemblies (spline type 72875, 72879; flange type 69346, 70412, 71803; and 72782, 74900, 75679, 76494, 77731).

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

Federal Register Abstract

Reduction Gear Assemblies

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_69-25-08.html
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AD Number:
69-25-08
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
Subject:
Reduction Gear Assemblies
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
02/19/1970
Make:
Lycoming Engines
Model:
GO-435-C2A | GO-435-C2A2 | GO-480-A1A | GO-480-B | GO-480-B1A6 | GO-480-B1B | GO-480-B1C | GO-480-B1...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: 69-25-08
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-938

AD NUMBER:   69-25-08

SUBJECT HEADING:   LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines

ACTION:  

SUMMARY:  

DATES:   Effective February 19, 1970.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
69-25-08 LYCOMING ENGINES: Amdt. 39-892 as amended by Amendment 39-938. Applies to Lycoming GO-435-C2A, GO-480, GSO-480 and IGSO-480 type engines using spline type reduction gear assemblies 72875 and 72879, GO-480 and GSO-480 type engines using flange type reduction gear assemblies 69346, 70412 and 71803 and IGO-540 and IGSO-540 type engines using reduction gear assemblies 72782, 74900, 75679, 76494 and 77731.

Compliance required unless already accomplished prior to the accumulation of six hundred (600) hours in service or 100 hours after the effective date of this AD whichever comes later for the GO-435, IGO-540 and IGSO-540 type engines and prior to the accumulation of seven hundred (700) hours in service or 100 hours after the effective date of this AD whichever comes later for GO-480, GSO-480 and IGSO-480 type engines. To prevent failure of the reduction gear assembly a one time inspection is to be accomplished as follows:

a. Check torque on reduction gearing pinion cage attaching nut.

1. If found to be in excess of 50 ft.-lbs. remove, inspect for damage and replace the oil retaining housing if necessary. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs. When the assembly is disassembled replace thrust bearing oil slinger P/N 68319 with P/N 77454.

2. If found to be less than 50 ft.-lbs. disassemble the assembly and insure that all components meet approved specifications and replace the thrust bearing oil slinger P/N 68319 and P/N 77454 and the oil retaining housing. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs.

b. If the pinion cage is secured with a spline nut it must be replaced with an approved hexagonal nut.

c. If the assembly has been rebuilt using thrust bearing oil slinger P/N 77454, stamp the suffix (-1) to the part number on the reduction gear housing.

Lycoming Service Bulletin No. 319A and Lycoming Service Instruction No. 1210A pertain to this subject.

Amendment 39-892 effective December 17, 1969.

This Amendment (39-938) is effective February 19, 1970.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_69-25-08.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
69-25-08
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines
Subject:
Reduction Gear Assemblies
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
02/19/1970
Make:
Lycoming Engines
Model:
GO-435-C2A | GO-435-C2A2 | GO-480-A1A | GO-480-B | GO-480-B1A6 | GO-480-B1B | GO-480-B1C | GO-480-B1...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: 69-25-08
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-938

AD NUMBER:   69-25-08

SUBJECT HEADING:   LYCOMING ENGINES Model GO-435-C2A, GO-480, GSO-480 and IGSO-480, and IGO-540 and IGSO-540 type Engines

ACTION:  

SUMMARY:  

DATES:   Effective February 19, 1970.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
69-25-08 LYCOMING ENGINES: Amdt. 39-892 as amended by Amendment 39-938. Applies to Lycoming GO-435-C2A, GO-480, GSO-480 and IGSO-480 type engines using spline type reduction gear assemblies 72875 and 72879, GO-480 and GSO-480 type engines using flange type reduction gear assemblies 69346, 70412 and 71803 and IGO-540 and IGSO-540 type engines using reduction gear assemblies 72782, 74900, 75679, 76494 and 77731.

Compliance required unless already accomplished prior to the accumulation of six hundred (600) hours in service or 100 hours after the effective date of this AD whichever comes later for the GO-435, IGO-540 and IGSO-540 type engines and prior to the accumulation of seven hundred (700) hours in service or 100 hours after the effective date of this AD whichever comes later for GO-480, GSO-480 and IGSO-480 type engines. To prevent failure of the reduction gear assembly a one time inspection is to be accomplished as follows:

a. Check torque on reduction gearing pinion cage attaching nut.

1. If found to be in excess of 50 ft.-lbs. remove, inspect for damage and replace the oil retaining housing if necessary. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs. When the assembly is disassembled replace thrust bearing oil slinger P/N 68319 with P/N 77454.

2. If found to be less than 50 ft.-lbs. disassemble the assembly and insure that all components meet approved specifications and replace the thrust bearing oil slinger P/N 68319 and P/N 77454 and the oil retaining housing. During assembly comply with part (b) using a new lockplate and a pinion cage attaching nut torque of 400 ft.-lbs.

b. If the pinion cage is secured with a spline nut it must be replaced with an approved hexagonal nut.

c. If the assembly has been rebuilt using thrust bearing oil slinger P/N 77454, stamp the suffix (-1) to the part number on the reduction gear housing.

Lycoming Service Bulletin No. 319A and Lycoming Service Instruction No. 1210A pertain to this subject.

Amendment 39-892 effective December 17, 1969.

This Amendment (39-938) is effective February 19, 1970.

FOOTER:

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Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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