# AD 82-15-02: Main And Tail Rotors

- Type: Airworthiness directive
- Status: Current
- Products: Hiller UH-12D, UH-12L, UH-12L4, UH-12E and UH-12E-L
- Effective: July 16, 1982
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-4416
- Registered aircraft: 132 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1E223CF2328A133686256A4E0043C655.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/82-15-02

## The airworthiness directive

82-15-02 HILLER AVIATION: Amendment 39-4416. Applies to Model UH-12D, UH- 12E, UH-12E4, UH-12E-L, UH-12L, UH-12L4, and military OH-23D, OH-23F and OH-23G series helicopters, certificated in all categories, through serial No. 5187.

Compliance required as indicated, unless already accomplished.

To prevent loss of power to the main and tail rotors, accomplish the following:

Within 50 hours' additional time in service after the effective date of this AD, remove the four P/N 21041 bolts and four AN 960-716L washers which attach the mercury clutch to the torsional coupling and replace with new P/N 21041 bolts and P/N 21074-3 washers in accordance with Part 2, Accomplishment Instruction, of Hiller Aviation Service Bulletin No. 21-2 dated January 20, 1982, or FAA approved equivalent. The four P/N 21041 bolts removed per this action must be considered unairworthy and marked accordingly.

NOTE: Hiller Model UH-12 series helicopters converted to turbine power by Supplemental Type Certificate (STC) SH178WE or SH177WE do not incorporate the subject parts and therefore are not affected by this AD unless restored to the original configuration.

Special flight permits may be issued in accordance with Sections 21.197 and 21.199 of the FAR to operate rotorcraft to a base for the accomplishment of inspections or modifications required by this AD.

Alternative inspections, modifications, or other actions which provide an equivalent level of safety may be used when approved by the Chief, Western Aircraft Certification Field Office, FAA Northwest Mountain Region.

This amendment supersedes AD 82-10-06. This amendment becomes effective July 16, 1982.

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4H11](https://openairdocs.org/tcds/4H11): Siam Hiller Holdings Inc.; names 2 of 2 models: UH-12E, UH-12E-L
- [TCDS H1WE](https://openairdocs.org/tcds/H1WE): Siam Hiller Holdings Inc.; names 2 of 2 models: UH-12L4, UH-12L
- [TCDS 4H10](https://openairdocs.org/tcds/4H10): Siam Hiller Holdings Inc.; names 1 of 1 models: UH-12D

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 132 (132 by airframe model, 0 by engine model)
- Makers: Hiller 129, Hiller-Osborn 2, Hiller-Rogerson Helicopter 1

Models with the most aircraft:

- [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e): 103 aircraft (airframe model)
- [Hiller UH-12D](https://openairdocs.org/model/hiller-uh-12d): 22 aircraft (airframe model)
- [Hiller UH-12L4](https://openairdocs.org/model/hiller-uh-12l4): 3 aircraft (airframe model)
- [Hiller-Osborn UH-12D](https://openairdocs.org/model/hiller-osborn-uh-12d): 2 aircraft (airframe model)
- [Hiller UH-12E-L](https://openairdocs.org/model/hiller-uh-12e-l): 1 aircraft (airframe model)
- [Hiller-Rogerson Helicopter UH12E](https://openairdocs.org/model/hiller-rogerson-helicopter-uh12e): 1 aircraft (airframe model)

All 7 models: https://openairdocs.org/ad/82-15-02/models.md
Every aircraft: https://openairdocs.org/ad/82-15-02/aircraft.md

## Related documents

- [STC SH177WE](https://openairdocs.org/stc/SH177WE): Installation of Allison 250-C20/250-C20B engine and related changes.. Siam Hiller Holdings Inc, Cited in the text
- [STC SH178WE](https://openairdocs.org/stc/SH178WE): Installation of Allison 250-C20/250-C20B engine and related changes. (UH-12E-L (4 place)). Siam Hiller Holdings Inc, Cited in the text

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