AD 77-26-01

77-26-01 HAWKER SIDDELEY AVIATION, LIMITED: Amendment 39-3099. Applies to DH/BH-125 airplanes, all series except 600A and 700A and excluding those airplanes with Modification 252239 embodied which introduces the Walter Kidde supply valve.

Compliance is required as indicated unless already accomplished.

To ensure the retainment of the threaded insert and prevent possible sudden discharge of the high pressure oxygen supply into the crew compartment, accomplish the following:

(a) Within 10 hours time in service after the effective date of this AD, locate the oxygen master supply valve and passenger supply valve, both P/N SDV 826-1, and check to assure that threaded insert in the gland bushing is secure and spot lock the insert all in accordance with the Section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Limited Alert Service Bulletin 35-A25, dated October 13, 1977, or an FAA-approved equivalent.

(b) Prior to installation of any oxygen supplyvalves from spares stock, unless already accomplished, check, tighten, and lock the insert in accordance with paragraph (a) of this AD.

This amendment becomes effective January 3, 1978.