AD 77-26-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Textron Aviation Inc. | BH.125 Series 400A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A/R-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 1A/S-522 | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A/R | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 3A/RA | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
| aircraft | Textron Aviation Inc. | DH.125 Series 400A | Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes |
Unsafe Condition
The threaded insert in the gland bushing of oxygen master supply valve and passenger supply valve (P/N SDV 826-1) may become loose, leading to possible sudden discharge of high pressure oxygen supply into the crew compartment.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 10 hours time in service after the effective date, locate the oxygen master supply valve and passenger supply valve (P/N SDV 826-1), check the threaded insert in the gland bushing for security, and spot lock the insert per Hawker Siddeley Aviation, Limited Alert Service Bulletin 35-A25 dated October 13, 1977 or FAA-approved equivalent. Before installing any oxygen supply valves from spares stock, check, tighten, and lock the insert as required.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 10 hours time in service after the effective date of this AD
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Affected Aircraft
HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 airplanes, all series except 600A and 700A and excluding those with Modification 252239 (Walter Kidde supply valve).
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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