# AD 78-01-06: Elevator Control Pulley Bracket

- Type: Airworthiness directive
- Status: Current
- Products: Textron BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 1A, DH.125 Series 1A-522, DH.125 Series 1A/R-522, DH.125 Series 1A/S-522, DH.125 Series 3A, DH.125 Series 3A/R, DH.125 Series 3A/RA, DH.125 Series 400A, HS.125 Series 600A and HS.125 Series 700A
- Effective: January 12, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-3108
- Registered aircraft: 26 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0E3F8066423A7C06862569A5007600E0.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/78-01-06

## The airworthiness directive

78-01-06 HAWKER SIDDELEY AVIATION, LIMITED: Amendment 39-3108. Applies to Model DH/BH/HS-125 airplanes, certificated in all categories.

Compliance is required as indicated unless already accomplished.

To prevent possible detachment of the bolts securing the elevator control pulley bracket to the aircraft structure, accomplish the following:

  (a) For BH/HS-125-600A aircraft, within 10 hours time in service after the effective date of this AD, replace the four bolts attaching the elevator control pulley bracket to the top of fin rear spar with 25-6CF 519 or NAS 1304-10H bolts and safety wire replacement bolts in pairs all in accordance with the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Modification Service Bulletin 27-122(2578), dated March 31, 1977, or an FAA-approved equivalent.

  (b) For all other DH/BH-125 aircraft, within 100 hours time in service after the effective date of this AD, replace the four bolts attaching the elevator control pulley bracket to the top of the fin rear spar in accordance with Paragraph (a) of this AD.

This amendment becomes effective January 12, 1978.

## 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 12 of 50 models: HS.125 Series 600A, HS.125 Series 700A, DH.125 Series 1A/R-522, BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 400A, DH.125 Series 3A/R, DH.125 Series 1A…

## 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: 26 (26 by airframe model, 0 by engine model)
- Makers: British Aerospace 14, Hawker Siddeley 11, Raytheon 1

Models with the most aircraft:

- [British Aerospace HS 125-700A](https://openairdocs.org/model/british-aerospace-hs-125-700a): 14 aircraft (airframe model)
- [Hawker Siddeley HS.125 SERIES 700A](https://openairdocs.org/model/hawker-siddeley-hs-125-series-700a): 7 aircraft (airframe model)
- [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)
- [Raytheon HS 125-700A](https://openairdocs.org/model/raytheon-hs-125-700a): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/78-01-06/models.md
Every aircraft: https://openairdocs.org/ad/78-01-06/aircraft.md

Its text cites no advisory circulars or STCs.

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