AD 66-22-04
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L | Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L4 | Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E-L | Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters |
Unsafe Condition
Failures of the mercury clutch due to cracking at the inner corners of driver lug slots in the side plates.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect the side plates for cracks using at least 8-power magnification. If cracks are found, replace clutch before further flight with a clutch of the same part number that has been inspected and found free of cracks.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 100 hours' time in service after the effective date of this AD
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Affected Aircraft
Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters equipped with Mercury Clutch Corporation P/N's 4578-6 and 4692-6, Clutch Serial Numbers 8584 through 9317.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Mercury Clutches
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_66-22-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 66-22-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters Subject: Mercury Clutches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/02/1966 Make: Hiller Aviation | Siam Hiller Holdings, Inc. Model: UH-12D | UH-12L | UH-12L4 | UH-12E | UH-12E-L Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 66-22-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-280 AD NUMBER: 66-22-04 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters ACTION: SUMMARY: DATES: Effective September 2, 1966. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 66-22-04 HILLER: Amdt. 39-280 Part 39 Federal Register September 2, 1966. Applies to Model UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters Equipped With Clutches, Mercury Clutch Corporation P/N's 4578-6 and 4692-6, Clutch Serial Numbers 8584 through 9317. Compliance required within the next 100 hours' time in service after the effective date of this AD, unless already accomplished. To prevent failures of the mercury clutch due to cracking at the inner corners of driver lug slots in the side plates, accomplish the following: (a) Visually inspect the side plates for cracks using at least 8-power magnification. (b) If cracks are found, replace clutch before further flight with a clutch of the same part number that has been inspected in accordance with this AD and found free of cracks. (Fairchild Hiller Service Information Letters Nos. 3052 and 5009, dated July 20, 1966, pertain to this subject). This directive effective September 2, 1966. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_66-22-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 66-22-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters Subject: Mercury Clutches Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/02/1966 Make: Hiller Aviation | Siam Hiller Holdings, Inc. Model: UH-12D | UH-12L | UH-12L4 | UH-12E | UH-12E-L Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 66-22-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-280 AD NUMBER: 66-22-04 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters ACTION: SUMMARY: DATES: Effective September 2, 1966. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 66-22-04 HILLER: Amdt. 39-280 Part 39 Federal Register September 2, 1966. Applies to Model UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters Equipped With Clutches, Mercury Clutch Corporation P/N's 4578-6 and 4692-6, Clutch Serial Numbers 8584 through 9317. Compliance required within the next 100 hours' time in service after the effective date of this AD, unless already accomplished. To prevent failures of the mercury clutch due to cracking at the inner corners of driver lug slots in the side plates, accomplish the following: (a) Visually inspect the side plates for cracks using at least 8-power magnification. (b) If cracks are found, replace clutch before further flight with a clutch of the same part number that has been inspected in accordance with this AD and found free of cracks. (Fairchild Hiller Service Information Letters Nos. 3052 and 5009, dated July 20, 1966, pertain to this subject). This directive effective September 2, 1966. FOOTER:
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Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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