AD 78-12-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Lycoming Engines | O-320-H1AD | AVCO LYCOMING Model O-320-H Series Engines |
| engine | Lycoming Engines | O-320-H1BD | AVCO LYCOMING Model O-320-H Series Engines |
| engine | Lycoming Engines | O-320-H2AD | AVCO LYCOMING Model O-320-H Series Engines |
| engine | Lycoming Engines | O-320-H2BD | AVCO LYCOMING Model O-320-H Series Engines |
| engine | Lycoming Engines | O-320-H3AD | AVCO LYCOMING Model O-320-H Series Engines |
| engine | Lycoming Engines | O-320-H3BD | AVCO LYCOMING Model O-320-H Series Engines |
Unsafe Condition
Oil pump failures due to insufficient clearance between the oil pump driving and driven impellers.
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Required Actions
Remove, inspect, and alter the oil pump body. Replace the oil pump driving impeller with P/N LW-15998 and the driven impeller with P/N LW-15999 per AVCO Lycoming Service Bulletin No. 423 or FAA-approved equivalent.
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Compliance Time
within the next 10 hours in service
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Affected Aircraft
AVCO Lycoming Model O-320-H series engines with serial numbers L-101-76 through L-3829-76, L-3831-76, L-3843-76 through L-3859-76, L-3864-76, L-3866-76, L-3871-76, L-3902-76 through L-3907-76 and all O-320-H series engines overhauled (remanufactured by Lycoming) before March 24, 1978.
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Federal Register Abstract
Oil Pump Body
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_78-12-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-12-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: AVCO LYCOMING Model O-320-H Series Engines Subject: Oil Pump Body Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/20/1978 Make: Lycoming Engines Model: O-320-H1AD | O-320-H1BD | O-320-H2AD | O-320-H2BD | O-320-H3AD | O-320-H3BD Product Type: Engine Product Subtype: Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 78-12-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3239 AD NUMBER: 78-12-08 SUBJECT HEADING: AVCO LYCOMING Model O-320-H Series Engines ACTION: SUMMARY: DATES: Effective June 20, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-12-08 AVCO LYCOMING: Amendment 39-3239. Applies to O-320-H series engines Serial Numbers L-101-76 through L-3829-76, L-3831-76, L-3843-76 through L-3859-76, L-3864-76, L-3866-76, L-3871-76, L-3902-76 through L-3907-76 and all O-320-H series engines overhauled (Remanufactured by Lycoming) before March 24, 1978. Compliance required within the next 10 hours in service, unless already accomplished. a. To prevent oil pump failures, remove, inspect and alter the oil pump body and replace the oil pump driving impeller with driving impeller P/N LW-15998 and the oil pump driven impeller with driven impeller P/N LW-15999 in accordance with AVCO Lycoming Service Bulletin No. 423 dated March 24, 1978, or FAA approved equivalent. b. Equivalent method of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. This amendment is effective June 20, 1978. FOOTER:
Document Text
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AD Final Rules - DRS_78-12-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-12-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: AVCO LYCOMING Model O-320-H Series Engines Subject: Oil Pump Body Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/20/1978 Make: Lycoming Engines Model: O-320-H1AD | O-320-H1BD | O-320-H2AD | O-320-H2BD | O-320-H3AD | O-320-H3BD 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: 78-12-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3239 AD NUMBER: 78-12-08 SUBJECT HEADING: AVCO LYCOMING Model O-320-H Series Engines ACTION: SUMMARY: DATES: Effective June 20, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-12-08 AVCO LYCOMING: Amendment 39-3239. Applies to O-320-H series engines Serial Numbers L-101-76 through L-3829-76, L-3831-76, L-3843-76 through L-3859-76, L-3864-76, L-3866-76, L-3871-76, L-3902-76 through L-3907-76 and all O-320-H series engines overhauled (Remanufactured by Lycoming) before March 24, 1978. Compliance required within the next 10 hours in service, unless already accomplished. a. To prevent oil pump failures, remove, inspect and alter the oil pump body and replace the oil pump driving impeller with driving impeller P/N LW-15998 and the oil pump driven impeller with driven impeller P/N LW-15999 in accordance with AVCO Lycoming Service Bulletin No. 423 dated March 24, 1978, or FAA approved equivalent. b. Equivalent method of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. This amendment is effective June 20, 1978. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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