AD 80-04-04 R1
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Lycoming Engines | IVO-540-A1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TIVO-540-A2A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-A1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-B1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-B1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-C1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-D1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-D1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-E1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-F1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-G1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-435-G1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-540-A1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1C | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1D | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1E | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-A1F | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-435-B1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A2A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B3 | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1C | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1D | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1E | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1F | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1H3 | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2C | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2D | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2E | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B2G | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C1C3 | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2A | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2B | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-C2C | AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines |
Unsafe Condition
Failure of the crankshaft flange bolts due to insufficient torque, fretting, galling, or metal transfer between mating surfaces.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Check crankshaft flange bolt nuts for 15 ft.-lbs. torque. Inspect flanges for cracks, fretting, galling, or metal transfer if torque is below 15 ft.-lbs. Remove deficient components and repair crankshaft bolt holes per Service Instruction 1209B. Install replacement bolts per Service Instruction 1209B. For engines without deficiencies, recheck torque every 600 hours until full compliance.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours in service after effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
AVCO Lycoming VO and TVO-435 series engines and VO, IVO, TVO, TIVO-540 series engines
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Crankshaft Flange Bolts
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_80-04-04_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-04-04 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines Subject: Crankshaft Flange Bolts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/18/1980 Make: Lycoming Engines Model: IVO-540-A1A | TIVO-540-A2A | TVO-435-A1A | TVO-435-B1A | TVO-435-B1B | TVO-435-C1A | TVO-435-D1A | T...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: 80-04-04 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3881 AD NUMBER: 80-04-04 R1 SUBJECT HEADING: AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines ACTION: SUMMARY: DATES: Effective August 18, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-04-04 R1 AVCO LYCOMING: Amendment 39-3691 as amended by Amendment 39-3881. Applies to all VO and TVO-435 series engines and to all VO, IVO, TVO and TIVO-540 series engines. To prevent possible failure of the crankshaft flange bolts perform the following, unless already accomplished: (a) Within the next 50 hours in service after effective date of this AD, engines that have accumulated 550 hours' or more time in service since new or overhaul must have the engine crankshaft flange to transmission drive coupling attaching bolt nuts checked for 15 ft.-lbs. torque measured in the tightening direction. If the torque on any attaching bolt nut is less than 15 ft.-lbs., the engine crankshaft flange and the helicopter transmission drive coupling flange must be inspected for cracks, fretting, galling, or for any metal transfer from one surface to its mating surface. Remove from service any crankshaft or drive coupling which shows such deficiencies. Prior to returning the engine to service accomplish the following: (1) Remove and discard all flange bolts. Measure all bolt holes in the crankshaft flange and repair if necessary in accordance with the requirements of AVCO Lycoming Service Instruction No. 1209B or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. (2) Install replacement bolts in accordance with Avco Lycoming Service Instruction No. 1209B paragraph 5 or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. Those engines which showed no such deficiencies or whose attaching bolt nut torques measured 15 ft.-lbs. may be returned to service, but the torque of the crankshaft flange attaching bolt nuts must be measured every 600 hours in service thereafter or until compliance with paragraphs (a)(1) and (a)(2) of this AD is accomplished. Amendment 39-3691 was effective February 8, 1980. This amendment 39-3881 is effective August 18, 1980. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_80-04-04_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-04-04 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines Subject: Crankshaft Flange Bolts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/18/1980 Make: Lycoming Engines Model: IVO-540-A1A | TIVO-540-A2A | TVO-435-A1A | TVO-435-B1A | TVO-435-B1B | TVO-435-C1A | TVO-435-D1A | T...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: 80-04-04 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3881 AD NUMBER: 80-04-04 R1 SUBJECT HEADING: AVCO LYCOMING Model VO and TVO-435 and VO, IVO, TVO and TIVO-540 Series Engines ACTION: SUMMARY: DATES: Effective August 18, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-04-04 R1 AVCO LYCOMING: Amendment 39-3691 as amended by Amendment 39-3881. Applies to all VO and TVO-435 series engines and to all VO, IVO, TVO and TIVO-540 series engines. To prevent possible failure of the crankshaft flange bolts perform the following, unless already accomplished: (a) Within the next 50 hours in service after effective date of this AD, engines that have accumulated 550 hours' or more time in service since new or overhaul must have the engine crankshaft flange to transmission drive coupling attaching bolt nuts checked for 15 ft.-lbs. torque measured in the tightening direction. If the torque on any attaching bolt nut is less than 15 ft.-lbs., the engine crankshaft flange and the helicopter transmission drive coupling flange must be inspected for cracks, fretting, galling, or for any metal transfer from one surface to its mating surface. Remove from service any crankshaft or drive coupling which shows such deficiencies. Prior to returning the engine to service accomplish the following: (1) Remove and discard all flange bolts. Measure all bolt holes in the crankshaft flange and repair if necessary in accordance with the requirements of AVCO Lycoming Service Instruction No. 1209B or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. (2) Install replacement bolts in accordance with Avco Lycoming Service Instruction No. 1209B paragraph 5 or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. Those engines which showed no such deficiencies or whose attaching bolt nut torques measured 15 ft.-lbs. may be returned to service, but the torque of the crankshaft flange attaching bolt nuts must be measured every 600 hours in service thereafter or until compliance with paragraphs (a)(1) and (a)(2) of this AD is accomplished. Amendment 39-3691 was effective February 8, 1980. This amendment 39-3881 is effective August 18, 1980. 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.
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