AD 90-15-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L | Airworthiness Directives; ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12L4 | Airworthiness Directives; ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 Series Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E-L | Airworthiness Directives; ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 Series Helicopters |
Unsafe Condition
Failure of a tail rotor blade assembly, which could result in loss of controllability of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Determine the part number and serial number of the tail rotor blade assemblies. Remove and replace any blade assembly with P/N 55073 and serial numbers listed in the AD before further flight. Report findings to the Seattle Aircraft Certification Office within 10 days of inspection. Record compliance in AD compliance records and helicopter log books.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Required prior to further flight, unless already accomplished.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 series helicopters, certificated in any category.
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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