# AD 81-06-06: Fuel Feed Lines

- Type: Airworthiness directive
- Status: Current
- Products: Textron BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 3A, DH.125 Series 3A/R, DH.125 Series 3A/RA, DH.125 Series 400A and HS.125 Series 600A with STC SA3870WE
- Effective: March 26, 1981
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-4065
- Registered aircraft: 4 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D1C14748F222B679862569F200725D26.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/81-06-06

## The airworthiness directive

81-06-06 BRITISH AEROSPACE: Amendment 39-4065. Applies to Model HS/DH/BH- 125 airplanes series -3A/R, -3A/RA, and -3A/RA with British Aerospace Modification 25/2600 installed; series -400A and -400A with British Aerospace Modification 25/2550 or STC SA3870WE installed; and series -600A and -600A with British Aerospace Modification 25/2468 installed, certificated in all categories.

Compliance is required as indicated, unless already accomplished.

To prevent restricted movement of the flap control unit input lever and chafing of the left engine fuel line due to possible interferences, accomplish the following:

  (a) Within 50 hours time in service after the effective date of this AD, inspect:

  (1) For chafing of the left engine fuel feed line; and

  (2) For recommended clearance between the fuel feed line and the flap control unit input lever in accordance with paragraph 2A(1), (2), and (3) of the Accomplishment Instructions of British Aerospace Service Bulletin28-69, Revision 1, dated June 25, 1979 (hereinafter referred to as the service bulletin) or an equivalent approved by the Chief, Aircraft Certification Staff, Federal Aviation Administration, Europe, Africa, and Middle East Office, Brussels, Belgium.

  (b) If as a result of the inspections required in paragraph (a) of this AD -

  (1) Chafing or other damage to the fuel line is found, before further flight, except that aircraft may be flown in accordance with FAR Section 21.197 to a base where the work can be performed, replace the fuel line with a serviceable fuel line of the same P/N.

  (2) Clearance between the engine fuel feed line and the flap control unit input lever is found to be less than 0.15 inches, before further flight, increase the clearance in accordance with paragraph 2A(4) of the service bulletin.

  (c) Upon completion of the actions required in paragraphs (a) and (b) of this AD, return the aircraft to service in accordance with paragraphs 2A(5) and 2A(6)of the service bulletin.

This amendment becomes effective March 26, 1981.

## 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 7 of 50 models: HS.125 Series 600A, BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 400A, DH.125 Series 3A/R, DH.125 Series 3A, 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/81-06-06/models.md
Every aircraft: https://openairdocs.org/ad/81-06-06/aircraft.md

## Related documents

- [STC SA3870WE](https://openairdocs.org/stc/SA3870WE): Installation of Garrett AiResearch TFE-731-3-1H engines and related changes.. AlliedSignal Aviation Services, Named in the applicability

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