AD 53-09-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | UH-12 | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
| aircraft | Hiller Aviation | UH-12A | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
| aircraft | Hiller Aviation | UH-12B | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
Unsafe Condition
Fatigue failure of the clevis head on the outboard tension torsion bar pins, P/N 51414-1.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect P/N 51414-1 pins to determine the fillet radius under the clevis head. Replace pins with radius less than 0.030 inch before further flight. Replace all pins after accumulating 500 hours of flight time.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
As soon as possible but no later than the next 25-hour inspection and as indicated in part C below.
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Affected Aircraft
Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters.
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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