AD 78-22-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; Hiller Model UH-12D, UH-12E, UH-23D, UH-23G, and H-23F Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Model UH-12D, UH-12E, UH-23D, UH-23G, and H-23F Helicopters |
Unsafe Condition
Failure of the main rotor blade Parson Part No. 2253-1101-03 and 2253-1101-04 antinode outboard retention system could result in a loss of the rotorcraft.
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Required Actions
Inspect the threaded end of the antinode bar outboard of the antinode weight anchor nut. If the thread major diameter is ≤0.3677 inches, replace the antinode bar assembly either by returning blades to Hiller Aviation/FAA-approved repair station or following Hiller Service Bulletin 51-4. Record measurements and report helicopter/blade details to FAA Western Region.
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Compliance Time
Before further flight after receipt of this AD
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Affected Aircraft
Hiller Model UH-12D, UH-12E, UH-23D, UH-23G, H-23F helicopters equipped with main rotor blades assembly Parson Part No. 2253-1101-03 or 2253-1101-04.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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