AD 78-23-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Models UH-12D, UH-12E, and UH-12E (4 Place) Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Models UH-12D, UH-12E, and UH-12E (4 Place) Helicopters |
Unsafe Condition
Failure of finite life components such as engine snubber assemblies, brackets, flyweight collective pitch ballast, bellcrank, tube, shaft, block assembly, arm assembly, scissor, and attaching bolts due to insufficient replacement periods or undocumentable service history.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect service history of listed finite life components within 50 hours time in service after the AD's effective date. Remove and replace components with insufficient replacement periods before further flight if service history is undocumentable. Replace components with remaining life if their replacement period exceeds helicopter total time within 500 hours time in service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within fifty (50) hours time in service after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Hiller Models UH-12D, UH-12E, and UH-12E (4 Place) helicopters, including Military Models UH-23D, OH-23G, H-23F and turbine-powered models, equipped with the listed finite life components.
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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