# AD 78-22-08: Flight/Engine Control

- Type: Airworthiness directive
- Status: Current
- Products: Hiller UH-12D and UH-12E with STC SH177WE or SH178WE
- Effective: November 30, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-3327
- Registered aircraft: 128 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/50A76C1D65BC755C86256A380060431A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-22-08

## The airworthiness directive

78-22-08 HILLER AVIATION: Amendment 39-3327. Applies to Model UH-12D and UH-12E helicopters, including the UH-12E 4-place configurations, which have been converted to turbine power in accordance with Soloy Conversions, Ltd., STC Nos. SH177WE and SH178WE respectively, certificated in all categories. Compliance required on or before January 1, 1979.

To prevent loss of flight control or engine control, accomplish the following:

  (a) Modify the integrated collective and N2 engine control system in accordance with Soloy Conversions, Ltd., Service Bulletin 06-560 dated October 6, 1978, or later FAA approved revision.

  (b) Unless already accomplished, remove from service certain N1 and N2 engine control cables as identified in Soloy Conversions, Ltd., Service Bulletin 06-560 dated October 6, 1978, or later FAA approved revisions. Install replacement cables in accordance with the same bulletin.

  (c) An equivalent modification may be approved by the Chief, Engineering andManufacturing Branch, FAA, Northwest Region.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1).

All persons affected by this directive who have not already received this document from the manufacturer, may obtain copies upon request to Soloy Conversions, Ltd., P.O. Box 60, Chehalis, Washington 98532. This document may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108.

This amendment becomes effective November 30, 1978.

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

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

## 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: 128 (128 by airframe model, 0 by engine model)
- Makers: Hiller 125, 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-Osborn UH-12D](https://openairdocs.org/model/hiller-osborn-uh-12d): 2 aircraft (airframe model)
- [Hiller-Rogerson Helicopter UH12E](https://openairdocs.org/model/hiller-rogerson-helicopter-uh12e): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/78-22-08/models.md
Every aircraft: https://openairdocs.org/ad/78-22-08/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, Named in the applicability
- [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, Named in the applicability

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.