AD 52-01-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | UH-12 | Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters |
| aircraft | Hiller Aviation | UH-12A | Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters |
| aircraft | Hiller Aviation | UH-12B | Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters |
Unsafe Condition
Failure of the main rotor blade collective pitch incidence arms (P/N 31114-1) due to possible minute cracks in the circumferential area of the flange radii.
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Required Actions
Inspect main blade incidence arms (P/N 31114-1) to determine if chrome plated arms are installed. If installed, remove and magnaflux or magnaglow inspect each arm for cracks. Replace arms immediately if cracks are found; reinspect at 100 hours service if under 100 hours, or comply with inspection intervals as specified.
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Compliance Time
Not later than the next 25-hour inspection or February 1, 1952, whichever occurs first.
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Affected Aircraft
Hiller Models UH-12, -12A, and -12B helicopters, serial numbers 104 and up, with chrome plated main rotor blade incidence arms P/N 31114-1.
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Federal Register Abstract
Collective Pitch Incidence Arms
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_52-01-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 52-01-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters Subject: Collective Pitch Incidence Arms Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 52-01-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 52-01-08 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 52-01-08 HILLER: Applies to All Models UH-12, -12A and -12B Helicopters, Serial Numbers 104 and Up. (Incorporating Chrome Plated Main Rotor Blade Incidence Arms P/N 31114-1.) Compliance required not later than the next 25-hour inspection, or not later than February 1, 1952, whichever occurs first and also as noted below. As a precautionary measure to preclude possible serious danger which could result from failure of the main rotor blade collective pitch incidence arms (P/N 31114-1), the following should be accomplished: (a) Inspect all main blade incidence arms (P/N 31114-1) to determine if chrome plated arms are installed. (b) If chrome plated arms are installed, remove and magnaflux or magnaglow inspect each arm for possible minute cracks in the circumferential area of the flange radii. (c) If the arm has had 100 hours service and cracks are not found, the part may be reinstalled and further compliance with this Note is not required. If the arm has less than 100 hours service, it must again be inspected at 100 hours or not to exceed 125 hours of service. If cracks are found in any arm, it must be replaced immediately. (d) This Note also applies to spare and replacement chrome plated arms which should be inspected at 25 and 100 hours service as indicated above. (Hiller Helicopter's Mandatory Service Bulletin No. 20 covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_52-01-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 52-01-08 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters Subject: Collective Pitch Incidence Arms Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B 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: 52-01-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 52-01-08 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, -12A and -12B Helicopters ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 52-01-08 HILLER: Applies to All Models UH-12, -12A and -12B Helicopters, Serial Numbers 104 and Up. (Incorporating Chrome Plated Main Rotor Blade Incidence Arms P/N 31114-1.) Compliance required not later than the next 25-hour inspection, or not later than February 1, 1952, whichever occurs first and also as noted below. As a precautionary measure to preclude possible serious danger which could result from failure of the main rotor blade collective pitch incidence arms (P/N 31114-1), the following should be accomplished: (a) Inspect all main blade incidence arms (P/N 31114-1) to determine if chrome plated arms are installed. (b) If chrome plated arms are installed, remove and magnaflux or magnaglow inspect each arm for possible minute cracks in the circumferential area of the flange radii. (c) If the arm has had 100 hours service and cracks are not found, the part may be reinstalled and further compliance with this Note is not required. If the arm has less than 100 hours service, it must again be inspected at 100 hours or not to exceed 125 hours of service. If cracks are found in any arm, it must be replaced immediately. (d) This Note also applies to spare and replacement chrome plated arms which should be inspected at 25 and 100 hours service as indicated above. (Hiller Helicopter's Mandatory Service Bulletin No. 20 covers this same subject.) 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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