AD 69-08-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Fairchild-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; Fairchild-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; Fairchild-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; Fairchild-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; Fairchild-Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L and UH-12L4 Helicopters |
Unsafe Condition
Fatigue failures of the tail rotor yoke, P/N 55046 and P/N 55046-5.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Conduct a magnetic-particle inspection and measure the tail rotor yoke fillet radius within 10 hours time in service after the effective date. If a crack is found or the fillet radius is less than 0.030 inches, remove the yoke from service. For fillet radii between 0.030 and 0.050 inches, conduct subsequent inspections every 50 hours and remove the yoke within 250 hours. Ensure replacement yokes have a fillet radius of at least 0.050 inches.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 10 hours time in service after the effective date of this AD
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Affected Aircraft
Fairchild-Hiller Models UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 helicopters with P/N 55046 and P/N 55046-5 tail rotor yokes.
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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