AD 71-25-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12 | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12A | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12B | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12C | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L4 | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E-L | Airworthiness Directives; Fairchild Hiller Model UH-12 Helicopters |
Unsafe Condition
Cracks in main rotor blade part number 53100 could result in blade failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect main rotor blade P/N 53100 for cracks using dye penetrant within 10 hours time in service after the effective date. Remove defective blades from service prior to further flight and report serial numbers to the specified FAA office.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 10 hours time in service after the effective date
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Affected Aircraft
Fairchild Hiller Model UH-12 helicopters certificated in all categories, including models UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12L, UH-12L4, UH-12E, and UH-12E-L.
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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