AD 59-05-05
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12 | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12A | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12B | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12C | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters |
Unsafe Condition
Cyclic control scissor casting P/N 34141 may develop cracks due to improper casting techniques, leading to failure in service.
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Required Actions
Visually inspect P/N 34141 casting for cracks prior to every flight and refueling if part has accumulated more than 275 hours. Remove the part from service before further flight if cracks are detected. Effective September 1, 1959, P/N 34141 must be removed from service prior to accumulating 275 hours total time. Replace with new forging P/N 34158 to discontinue inspections.
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Compliance Time
Prior to further flight if cracks are detected; effective September 1, 1959, before accumulating 275 hours total time.
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Affected Aircraft
Hiller Models UH-12, UH-12A, UH-12B, UH-12C (serial numbers 934 and up), UH-12D (all serial numbers), and spare P/N 34141 castings delivered after July 1, 1957.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Cyclic Control Scissor Casting
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_59-05-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-05-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters Subject: Cyclic Control Scissor Casting Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation | Siam Hiller Holdings, Inc. Model: UH-12 | UH-12A | UH-12B | UH-12C | UH-12D | UH-12E 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: 59-05-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-05-05 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-05-05 HILLER: Applies As Follows: (a) UH-12, UH-12A, and UH-12B Incorporating Hiller Service Bulletin Numbers 50 or 50A After July 1, 1957. (b) UH-12C, Serial Numbers 934 and Up. (c) UH-12D, All Serial Numbers. (d) All Spare P/N 34141 Castings Delivered By Hiller After July 1, 1957. All UH-12 Series and All Serial Numbers Incorporating These Spares Are Affected. Compliance required as indicated. Due to improper casting techniques, two cyclic control scissor castings, P/N 34141, have failed in service on Model H-23D helicopters. As there is a possibility that additional P/N 34141 castings are defective, the following measure are required to detect cracks and prevent further failures: (1) Prior to every flight and refueling, visually inspect P/N 34141 casting for cracks if part has accumulated more than 275 hours. If cracks are detected, the part must be removed from service prior to further flight. (2) Effective September 1, 1959, P/N 34141 casting (including basic number and all dash numbers) must be removed from service prior to accumulation of 275 hours total time. (3) Upon replacement with a new forging P/N 34158, the special inspection of item (1) may be discontinued. This forging has unlimited service life. FOOTER:
Document Text
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AD Final Rules - DRS_59-05-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-05-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters Subject: Cyclic Control Scissor Casting Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation | Siam Hiller Holdings, Inc. Model: UH-12 | UH-12A | UH-12B | UH-12C | UH-12D | UH-12E 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: 59-05-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-05-05 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, UH-12C, and UH-12D Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-05-05 HILLER: Applies As Follows: (a) UH-12, UH-12A, and UH-12B Incorporating Hiller Service Bulletin Numbers 50 or 50A After July 1, 1957. (b) UH-12C, Serial Numbers 934 and Up. (c) UH-12D, All Serial Numbers. (d) All Spare P/N 34141 Castings Delivered By Hiller After July 1, 1957. All UH-12 Series and All Serial Numbers Incorporating These Spares Are Affected. Compliance required as indicated. Due to improper casting techniques, two cyclic control scissor castings, P/N 34141, have failed in service on Model H-23D helicopters. As there is a possibility that additional P/N 34141 castings are defective, the following measure are required to detect cracks and prevent further failures: (1) Prior to every flight and refueling, visually inspect P/N 34141 casting for cracks if part has accumulated more than 275 hours. If cracks are detected, the part must be removed from service prior to further flight. (2) Effective September 1, 1959, P/N 34141 casting (including basic number and all dash numbers) must be removed from service prior to accumulation of 275 hours total time. (3) Upon replacement with a new forging P/N 34158, the special inspection of item (1) may be discontinued. This forging has unlimited service life. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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