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
AI-generated summary from the source AD text. Verify against the official source before acting.
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.
Federal Register Abstract
Oxygen Supply
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_77-26-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-26-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes Subject: Oxygen Supply Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 01/03/1978 Make: Textron Aviation Inc. Model: BH.125 Series 400A | DH.125 Series 1A | DH.125 Series 1A-522 | DH.125 Series 1A/R-522 | DH.125 Serie...Show more Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 77-26-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3099 AD NUMBER: 77-26-01 SUBJECT HEADING: Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes ACTION: SUMMARY: DATES: Effective January 3, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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 supply valves 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. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_77-26-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-26-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes Subject: Oxygen Supply Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 01/03/1978 Make: Textron Aviation Inc. Model: BH.125 Series 400A | DH.125 Series 1A | DH.125 Series 1A-522 | DH.125 Series 1A/R-522 | DH.125 Serie...Show more Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 77-26-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3099 AD NUMBER: 77-26-01 SUBJECT HEADING: Airworthiness Directives; HAWKER SIDDELEY AVIATION, LIMITED Model DH/BH-125 Airplanes ACTION: SUMMARY: DATES: Effective January 3, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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 supply valves 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. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2023-10-02
final ruleAirworthiness Directives; Transport and Commuter Category Airplanes
Unsafe Condition: Radio altimeter anomalies that are undetected by the automation or pilot, particularly close to the ground (e.g., landing flare), could lead to loss of continued safe flight and landing. Additional...
2011-01-09
final ruleAirworthiness Directives; B/E Aerospace Protective Breathing Equipment (PBE) Part Number 119003-11 Installed on Various Transport Airplanes
Unsafe Condition: Potentially defective potassium superoxide canisters used in PBE units could result in an exothermic reaction and ignition.
2006-01-04
final ruleAirworthiness Directives; Raytheon Model DH.125, HS.125, and BH.125 Series Airplanes; Model BAe.125 Series 800A (C-29A and U-125), 800B, 1000A, and 1000B Airplanes; and Model Hawker 800 (including variant U-125A), and 1000 Airplanes
Unsafe Condition: The fan venturi overheated and produced smoke while the airplane was on the ground, potentially causing heat and fire damage to adjacent equipment, which could result in smoke in the cabin and/or b...
2005-03-16
final ruleAirworthiness Directives; Raytheon Model DH.125, HS.125, and BH.125 Series Airplanes; BAe.125 Series 800A (C-29A and U-125) and 800B Airplanes; and Hawker 800 (Including Variant U-125A) and 800XP Airplanes; Equipped with TFE731 Engines
Unsafe Condition: Insulation on the wire harness passing through the firewall fairlead ignited on the fuselage side of the firewall, potentially causing ignition of outgassing wire insulation and leading to an uncon...
