AD 78-18-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Models UH-12D and UH-12E Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Models UH-12D and UH-12E Helicopters |
Unsafe Condition
Drive shaft failure due to internal corrosion and subsequent helicopter structural and control system damage.
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Required Actions
Perform inspection and modifications and/or replacements of the Soloy P/N 560-2408 shaft in accordance with Soloy Conversions, Limited Service Bulletin 05-560 dated May 19, 1978, or later FAA approved revisions. Equivalent methods of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region.
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Compliance Time
Within the next 600 hours time in service, or 6 months calendar time, whichever occurs first after the effective date of this AD.
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Affected Aircraft
Hiller Aviation | Siam Hiller Holdings, Inc. Models UH-12D and UH-12E helicopters converted to turbine power under Soloy Conversions, Limited STC Nos. SH177WE and SH178WE respectively.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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