# AD 64-06-07: Stability Augmentation Systems

- Type: Airworthiness directive
- Status: Current
- Products: Columbia Helicopters 107-II
- Effective: March 7, 1964
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Registered aircraft: 12 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/640A5C10E5DD0E1886256A34005B5B12.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/64-06-07

## The airworthiness directive

64-06-07 VERTOL: Amdt. 697 Part 507 Federal Register March 7, 1964. Applies to All Model 107-II Helicopters.

Compliance required within 25 hours' time in service after the effective date of this AD.

To prevent recurrence of a serious lurching condition which has been encountered on this model helicopter, modify each stability augmentation system to derive a.c. power from its respective generator instead of the essential bus, as follows:

Remove the present a.c. electrical circuit wiring from terminals A3 and B3 of the a.c. instrument relay and from the "B" phase of the a.c. bus. Connect terminals A3 and B3 of the instrument relay to the terminal T2 of the a.c. feeder relay No. 1 and a.c. feeder relay No. 2 respectively.

(Vertol 107-II Service Bulletin No. 107-118 dated December 6, 1963, covers the same subject.) This directive effective March 7, 1964.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1H16](https://openairdocs.org/tcds/1H16): Columbia Helicopters Inc.; names 1 of 1 models: 107-II

## 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: 12 (12 by airframe model, 0 by engine model)
- Makers: Boeing-Vertol 7, Columbia Helicopters 2, Vertol 2, Boeing V-Columbia Helicopters 1

Models with the most aircraft:

- [Boeing-Vertol 107-II](https://openairdocs.org/model/boeing-vertol-107-ii): 7 aircraft (airframe model)
- [Columbia Helicopters 107-II](https://openairdocs.org/model/columbia-helicopters-107-ii): 2 aircraft (airframe model)
- [Vertol 107-II](https://openairdocs.org/model/vertol-107-ii): 2 aircraft (airframe model)
- [Boeing V-Columbia Helicopters 107-II](https://openairdocs.org/model/boeing-v-columbia-helicopters-107-ii): 1 aircraft (airframe model)

All 4 models: https://openairdocs.org/ad/64-06-07/models.md
Every aircraft: https://openairdocs.org/ad/64-06-07/aircraft.md

Its text cites no advisory circulars or STCs.

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