AD 59-05-05
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.
AI-generated summary from the source AD text. Verify against the official source before acting.
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.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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