AD 80-07-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12 | Airworthiness Directives; HILLER HELICOPTERS Model UH-12D, UH-12E and UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12D | Airworthiness Directives; HILLER HELICOPTERS Model UH-12D, UH-12E and UH-12 Helicopters |
| aircraft | Hiller Aviation | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; HILLER HELICOPTERS Model UH-12D, UH-12E and UH-12 Helicopters |
Unsafe Condition
Fatigue failure of the main rotor blade anti-node bars.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the threaded ends of the anti-node bar per Hiller Aviation Service Bulletin No. 51-5. Replace the anti-node bar if threads are cut or if evidence of thread condition is unsatisfactory. Reinstall with care if threads are rolled and total time is less than 6670 hours.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Before the accumulation of 2500 hours' time in service, or within 10 additional hours' time in service on main rotor blades with 2500 or more hours' time in service on the effective date of this AD, whichever occurs sooner.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Hiller Helicopters Model UH-12D, UH-12E, UH-12 (4 place), military models UH-23D, OH-23G, H-23F, and turbine-powered models equipped with main rotor blade assembly Parsons P/N 2253-1101-03 or 2253-1101-04.
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
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.