# Airworthiness Directives; Hiller Aircraft Corporation Model UH- 12A, UH-12B, UH-12C, UH-12D, and UH-12E Helicopters
> **Rule** · Final rule; request for comments. · Published 1995-06-08 · Effective 1995-06-23 · 60 FR 30184
## Document
- **Document number:** 95-13410
- **Category:** airworthiness
- **Manufacturer:** Hiller
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 60 FR 30184
- **Publication date:** 1995-06-08
- **Effective date:** 1995-06-23
- **FAA docket:** Docket No. 95-SW-13-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to Hiller Aircraft Corporation (Hiller) Model UH-12A, UH- 12B, UH- [[Page 30185]] 12C, UH-12D, and UH-12E helicopters. This action requires a dye-penetrant inspection of the head of the main rotor outboard tension-torsion (T-T) bar pin for cracks; a visual inspection of the outboard T-T bar pin for proper alignment, and an adjustment, if necessary; and, installation of shims at the inboard end of the drag strut. This amendment is prompted by two accidents involving failure of the outboard T-T bar pin on Hiller UH-12E helicopters. The actions specified by this AD are intended to prevent cracks in the head area of the outboard T-T bar pin, which could result in loss of in-plane stability of the main rotor blade and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1995/06/08/95-13410/airworthiness-directives-hiller-aircraft-corporation-model-uh--12a-uh-12b-uh-12c-uh-12d-and-uh-12e)
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