AD 68-08-08
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Lycoming Engines | IGSO-480-A1A6 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | IGSO-480-A1B6 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | IGSO-480-A1C6 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | IGSO-480-A1F6 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | IVO-360-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | IVO-540-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TIVO-540-A2A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-B1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-B1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-C1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-D1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-D1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-E1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-F1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-G1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-360-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-360-A1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-360-B1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1C | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1D | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1E | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1F | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-B1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A2A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B3 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1C | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1D | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1E | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1F | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1H3 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2C | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2D | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2E | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2G | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1C3 | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2A | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2B | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2C | LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines |
Unsafe Condition
Valve failures due to the use of P/N 76289 hydraulic valve lifter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace hydraulic lifter P/N 76289 with P/N 78289 within specified time-in-service windows based on engine model and usage.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
(a) TVO-435, VO-540, IVO-540, and TIVO-540 Series engines: within 50 hours' time in service after AD effective date. (b) VO-360, VO-435, and IGSO-480 Series engines with <600 hours on P/N 76289: prior to 650 hours' time in service. (c) VO-360, IVO-360, VO-345, and IGSO-480 Series engines with ≥600 hours on P/N 76289: within next 50 hours' time in service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Lycoming Engines: IGSO-480-A1A6, -A1B6, -A1C6, -A1F6; IVO-360-A1A; IVO-540-A1A; TIVO-540; VO-345, VO-360, VO-435, VO-540, TVO-435 Series engines with P/N 76289 hydraulic valve lifter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Hydraulic Valve
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_68-08-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 68-08-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIV...Show more Subject: Hydraulic Valve Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/19/1968 Make: Lycoming Engines Model: IGSO-480-A1A6 | IGSO-480-A1B6 | IGSO-480-A1C6 | IGSO-480-A1F6 | IVO-360-A1A | IVO-540-A1A | TIVO-540...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: 68-08-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-584 AD NUMBER: 68-08-08 SUBJECT HEADING: LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines ACTION: SUMMARY: DATES: Effective May 19, 1968. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 68-08-08 LYCOMING: Amendment 39-584. Applies to VO, IVO-360 Series: VO, TVO-435 Series; IGSO-480 Series excluding models IGSO-480-A1D6, -A1E6, -A1G6; VO, IVO, TIVO-540 Series engines which incorporate the P/N 76289 hydraulic valve lifter. Compliance required as indicated. To prevent further valve failures replace hydraulic lifter P/N 76289 with P/N 78289 at the time in service specified below: (a) TVO-435, VO-540, IVO-540, and TIVO-540 Series engines shall comply within 50 hours' time in service after the effective date of this AD. (b) VO-360, VO-435, and IGSO-480 Series engines with less than 600 hours' time in service on P/N 76289 as of the effective date of this AD, shall comply prior to the accumulation of 650 hours' time in service on P/N 76289. (c) VO-360, IVO-360, VO-345, and IGSO-480 Series engines with 600 or more hours' time in service on P/N 76289 as of the effective date of this AD shall comply within the next 50 hours' time in service. (NOTE: Lycoming Service Bulletin No. 314A provides serial numbers of new and factory remanufactured engines which have the P/N 76289 hydraulic valve lifter.) This amendment effective May 19, 1968. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_68-08-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 68-08-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIV...Show more Subject: Hydraulic Valve Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/19/1968 Make: Lycoming Engines Model: IGSO-480-A1A6 | IGSO-480-A1B6 | IGSO-480-A1C6 | IGSO-480-A1F6 | IVO-360-A1A | IVO-540-A1A | TIVO-540...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: 68-08-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-584 AD NUMBER: 68-08-08 SUBJECT HEADING: LYCOMING Model VO, IVO-360 Series: VO, TVO-435 Series Engines; IGSO-480 Series Engines; VO, IVO, TIVO-540 Series Engines ACTION: SUMMARY: DATES: Effective May 19, 1968. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 68-08-08 LYCOMING: Amendment 39-584. Applies to VO, IVO-360 Series: VO, TVO-435 Series; IGSO-480 Series excluding models IGSO-480-A1D6, -A1E6, -A1G6; VO, IVO, TIVO-540 Series engines which incorporate the P/N 76289 hydraulic valve lifter. Compliance required as indicated. To prevent further valve failures replace hydraulic lifter P/N 76289 with P/N 78289 at the time in service specified below: (a) TVO-435, VO-540, IVO-540, and TIVO-540 Series engines shall comply within 50 hours' time in service after the effective date of this AD. (b) VO-360, VO-435, and IGSO-480 Series engines with less than 600 hours' time in service on P/N 76289 as of the effective date of this AD, shall comply prior to the accumulation of 650 hours' time in service on P/N 76289. (c) VO-360, IVO-360, VO-345, and IGSO-480 Series engines with 600 or more hours' time in service on P/N 76289 as of the effective date of this AD shall comply within the next 50 hours' time in service. (NOTE: Lycoming Service Bulletin No. 314A provides serial numbers of new and factory remanufactured engines which have the P/N 76289 hydraulic valve lifter.) This amendment effective May 19, 1968. FOOTER:
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Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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