# AD 83-15-01: Relay Replacement Check

- Type: Airworthiness directive
- Status: Current
- Products: BAE Systems HS 748 Series 2A
- Effective: August 1, 1983
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-4690
- Registered aircraft: 2 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7FA4F809D6CD8B4D862569EB005A9981.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/83-15-01

## The airworthiness directive

83-15-01 BRITISH AEROSPACE: Amendment 39-4690. Applies to H.S. 748 Series 2A airplanes certificated in all categories. Compliance is required as indicated. To assure that propeller control circuit relays have proper resistance levels for the internal insulation and to correct the wiring connections to the propeller control circuit and thereby prevent multiple propeller feathering, accomplish the following, unless already accomplished:

1. Within 100 hours time in service after the effective date of this AD, and prior to each installation of a replacement relay, conduct an insulation resistance check of relays 34 and 35, type 7CZ105648/1 or 7CZ105648/2 in the propeller control circuit in accordance with paragraph 2.A or 2.B, as appropriate, Accomplishment Instructions of British Aerospace H.S. 748 Aircraft Service Bulletin 61/31 dated January 1980. Replace any relay with less than 50 megohms resistance. Reconnect the wiring to relays 34 and 35 in accordance with paragraph 2.Cof the service bulletin and conduct the propeller auto feathering check in accordance with paragraph 2.D of the service bulletin.

2. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

3. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD.

This amendment becomes effective August 1, 1983.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A24EU](https://openairdocs.org/tcds/A24EU): BAE Systems (Operations) Limited; names 1 of 2 models: HS 748 Series 2A

## 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: 2 (2 by airframe model, 0 by engine model)
- Makers: British Aerospace 2

Models with the most aircraft:

- [British Aerospace HS-748-2A](https://openairdocs.org/model/british-aerospace-hs-748-2a): 2 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/83-15-01/models.md
Every aircraft: https://openairdocs.org/ad/83-15-01/aircraft.md

Its text cites no advisory circulars or STCs.

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