# AD 78-13-02: Weather Radar Receiver/Transmitter

- Type: Airworthiness directive
- Status: Current
- Products: Textron BH.125 Series 600A, HS.125 Series 600A and HS.125 Series 700A
- Effective: July 5, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-3245
- Registered aircraft: 22 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/037F867349ED3AE8862569A70056F1E6.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/78-13-02

## The airworthiness directive

78-13-02 BRITISH AEROSPACE: Amendment 39-3245. Applies to Hawker Siddeley Model BH/HS-125 Series 600A and 700A airplanes, certificated in all categories, that have either the RCA AVQ21 or Primus 40 weather radar systems installed.

Compliance required as indicated.

To prevent failure of the restraint provisions for the weather radar receiver/transmitter, accomplish the following:

  (a) Within 10 hours time in service after the effective date of this AD, unless already accomplished within the last 40 hours time in service, and thereafter at intervals not to exceed 50 hours time in service from the last inspection, inspect the support brackets for cracks and the "T" bolts for failure of the brazing in accordance with section 2, "Accomplishment Instructions" of British Aerospace Alert Service Bulletin 34-A134, dated April 1, 1978, or an FAA approved equivalent.

  (b) If a crack in a support bracket or a failure of the brazing of the "T" bolt is found during an inspection required by paragraph (a) of this AD, before further flight, except that the airplane may be flown in accordance with FAR 21.197 and 21.199 to a base where the replacement can be accomplished, replace the mounting tray with a serviceable part of the same part number, or repair the existing mounting tray in accordance with an FAA approved repair scheme and continue to inspect in accordance with paragraph (a) of this AD, or replace the mounting tray in accordance with paragraph (c) of this AD.

  (c) The inspections required by this AD may be discontinued upon replacement of the mounting tray with an improved standard tray, P/N 1719353-501 (Rev. E), in accordance with British Aerospace Modification 258171 or an FAA approved equivalent.

This amendment becomes effective July 5, 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 3 of 50 models: HS.125 Series 600A, HS.125 Series 700A, BH.125 Series 600A

## 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: 22 (22 by airframe model, 0 by engine model)
- Makers: British Aerospace 14, Hawker Siddeley 7, 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)
- [Raytheon HS 125-700A](https://openairdocs.org/model/raytheon-hs-125-700a): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/78-13-02/models.md
Every aircraft: https://openairdocs.org/ad/78-13-02/aircraft.md

Its text cites no advisory circulars or STCs.

---
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.