# AD 77-13-09 R1: Structural Integrity of Bulkhead

- 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 and DH.125 Series 400A
- Effective: June 1, 1984
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-4854
- Registered aircraft: 4 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9AC0341980A26634862569A50064F2A9.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/77-13-09-R1

## The airworthiness directive

77-13-09 R1 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2934 as amended by Amendment 39-4854. Applies to Model DH/BH 125 airplanes series 1A up to and including series 600A certificated in all categories.

A. Prior to the accumulation of 6600 total landings or upon reaching 10 years after the date of manufacture of the airplane, whichever occurs first, if not already accomplished, incorporate Hawker Siddeley modifications 25-2402 and 25-2207 in accordance with Section 2, Accomplishment Instructions, of Hawker Siddeley Aviation, Ltd., Service Bulletin 53-46-(2402), Revision 2, dated February 16, 1976. Airplanes which have already exceeded 6500 landings or are over 9-1/2 years from date of manufacture must be modified within the next 100 landings or 6 months after the effective date of this amendment, whichever occurs first.

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

C. 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.

Amendment 39-2934 became effective July 25, 1977.

This Amendment 39-4854 becomes effective June 1, 1984.

## 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 10 of 50 models: 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, DH.125 Series 1A-522, DH.125 Series 3A…

## 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/77-13-09-R1/models.md
Every aircraft: https://openairdocs.org/ad/77-13-09-R1/aircraft.md

Its text cites no advisory circulars or STCs.

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