# AD 76-17-06: Airbrake Operating Circuit

- Type: Airworthiness directive
- Status: Current
- Products: Textron BH.125 Series 400A, DH.125 Series 1A, DH.125 Series 1A-522, DH.125 Series 1A/S-522, DH.125 Series 3A, DH.125 Series 3A/R, DH.125 Series 3A/RA and DH.125 Series 400A
- Effective: September 27, 1976
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-2705
- Registered aircraft: 4 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/382F7F5B3CF76207862569A500641901.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/76-17-06

## The airworthiness directive

76-17-06 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2705. Applies to Model DH/BH-125 airplanes Series 400A, S/N NA-711 through NA-758 and all Model DH/BH-125 airplanes Series 1A, 1A-522, 1A/S-522, 3A, 3AR, 3ARA, certificated in all categories.

Compliance is required within the next 200 hours time in service after the effective date of this AD, unless already accomplished.

To prevent possible unwanted deployment of airbrakes inflight, accomplish the following:

a) For all aircraft except those altered to include airbrake servodynes P/N AIR 46520/0 and 46521/0 in accordance with the Part D Supplement of Hawker Siddeley Aviation Ltd., Modification 252174, Service Bulletin SB 27-86-(2174), dated March 29, 1972, modify the airbrake servodynes, P/N AIR 45398 and 45399, in accordance with Part A of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation Ltd., Service Bulletin 27-86-(2174), Revision 4, dated March 29, 1972, or an FAA-approved equivalent.

b) For all aircraft, modify the airbrake operating circuit (R/H and L/H) in accordance with Part C of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin 27-86-(2174), Revision 4, dated March 29, 1972, or an FAA-approved equivalent.

This amendment becomes effective September 27, 1976.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A3EU](https://openairdocs.org/tcds/A3EU): Textron Aviation Inc.; names 8 of 50 models: BH.125 Series 400A, DH.125 Series 400A, DH.125 Series 3A/R, DH.125 Series 1A, DH.125 Series 1A-522, DH.125 Series 3A, DH.125 Series 1A/S-522, DH.125 Series 3A/RA

## 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: 4 (4 by airframe model, 0 by engine model)
- Makers: Hawker Siddeley 4

Models with the most aircraft:

- [Hawker Siddeley BH.125-400A](https://openairdocs.org/model/hawker-siddeley-bh-125-400a): 2 aircraft (airframe model)
- [Hawker Siddeley DH.125-3A/RA](https://openairdocs.org/model/hawker-siddeley-dh-125-3a-ra): 2 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/76-17-06/models.md
Every aircraft: https://openairdocs.org/ad/76-17-06/aircraft.md

Its text cites no advisory circulars or STCs.

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