AD 59-25-03
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12 | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12A | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12B | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12C | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters |
Unsafe Condition
Contact between the lower cyclic scissors and the filister head screws attaching the wobble plate shield can result in damage to the lower scissors and subsequent loss of cyclic control.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Daily inspect the lower cyclic scissors (P/N 34158 or P/N 34141) for damage due to striking the wobble plate shield attachment screws. Replace damaged scissors prior to next flight. Replace filister head screws with AN 509-8R4 flush head screws by January 1, 1960, following Hiller Service Bulletins No. 87 or No. 2004.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Daily inspections required; screw replacement required not later than January 1, 1960. Damaged scissors must be replaced prior to next flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Hiller Model UH-12, UH-12A, UH-12B, UH-12C, all UH-12D serial numbers, and UH-12E serials 942, 954, and 2001 through 2018.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Wobble Plate Screws
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_59-25-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-25-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters Subject: Wobble Plate Screws 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: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 59-25-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-25-03 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-25-03 HILLER: Applies to Hiller UH Series Helicopters As Follows: (a) UH-12 and UH-12A - incorporating both P/N 34126 wobble plate shield and P/N 34158 forged lower cyclic scissors. (b) UH-12B and UH-12C - incorporating the P/N 34158 forged lower cyclic scissors. (c) UH-12D - all Serial Numbers. (d) UH-12E - Serials 942, 954, and 2001 through 2018. Compliance required as indicated. To prevent contact between the lower cyclic scissors and the filister head screws attaching the wobble plate shield, which can result in damage to the lower scissors and subsequent loss of cyclic control, the following inspection and rework are required. (1) Daily inspect the lower cyclic scissors P/N 34158 on all models, or P/N 34141 on Models UH-12D and UH-12E for damage due to striking the wobble plate shield attachment screws. Damaged scissors must be replaced prior to next flight. (2) Not later than January 1, 1960, replace the filister head screws attaching the wobble plate shield with AN 509-8R4 flush head screws in accordance with the procedures in Hiller Service Bulletins No. 87 or No. 2004. (3) Upon accomplished of item (2) the inspections of item (1) may be discontinued. FOOTER:
Document Text
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AD Final Rules - DRS_59-25-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 59-25-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters Subject: Wobble Plate Screws 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: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 59-25-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 59-25-03 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12, -12A, -12B, -12C, -12D, -12E Series Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 59-25-03 HILLER: Applies to Hiller UH Series Helicopters As Follows: (a) UH-12 and UH-12A - incorporating both P/N 34126 wobble plate shield and P/N 34158 forged lower cyclic scissors. (b) UH-12B and UH-12C - incorporating the P/N 34158 forged lower cyclic scissors. (c) UH-12D - all Serial Numbers. (d) UH-12E - Serials 942, 954, and 2001 through 2018. Compliance required as indicated. To prevent contact between the lower cyclic scissors and the filister head screws attaching the wobble plate shield, which can result in damage to the lower scissors and subsequent loss of cyclic control, the following inspection and rework are required. (1) Daily inspect the lower cyclic scissors P/N 34158 on all models, or P/N 34141 on Models UH-12D and UH-12E for damage due to striking the wobble plate shield attachment screws. Damaged scissors must be replaced prior to next flight. (2) Not later than January 1, 1960, replace the filister head screws attaching the wobble plate shield with AN 509-8R4 flush head screws in accordance with the procedures in Hiller Service Bulletins No. 87 or No. 2004. (3) Upon accomplished of item (2) the inspections of item (1) may be discontinued. FOOTER:
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Retrieved: Apr 8, 2026
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