AD 75-17-21

final rule

Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes

AD Number
75-17-21
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Textron Aviation Inc. BH.125 Series 400A Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. BH.125 Series 600A Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 1A Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 1A-522 Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 1A/R-522 Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 1A/S-522 Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 3A Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 3A/R Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 3A/RA Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
aircraft Textron Aviation Inc. DH.125 Series 400A Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes

Unsafe Condition

Rapid loss of cabin pressurization due to displacement of Hellerman type cabin pressure seal bungs.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect all Hellerman type cabin pressure seal bungs for displacement within 50 hours time in service after the effective date. Rework as necessary per Maintenance Manual instructions and conduct a cabin leak rate check after reinstallation.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

within 50 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, LTD Models DH-125 and BH-125 airplanes certificated in all categories.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Cabin Pressurization

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_75-17-21.html
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AD Number:
75-17-21
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
Subject:
Cabin Pressurization
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/19/1975
Make:
Textron Aviation Inc.
Model:
BH.125 Series 400A | BH.125 Series 600A | DH.125 Series 1A | DH.125 Series 1A-522 | DH.125 Series 1A...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: 75-17-21
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2323

AD NUMBER:   75-17-21

SUBJECT HEADING:   Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective August 19, 1975.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-17-21 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2323. Applies to DH-125 and BH-125 airplanes certificated in all categories.

Compliance required as indicated.

To prevent possible rapid loss of cabin pressurization, accomplish the following:

Within 50 hours time in service after the effective date of this AD, unless already accomplished, inspect all Hellerman type cabin pressure seal bungs for displacement and rework as necessary in accordance with the following:

(a) Locate all Hellerman type cabin pressure seal bungs for the particular aircraft being inspected.

NOTE: Refer to the relevant aircraft wiring diagram manual (2 volumes) and to the maintenance practices in the Maintenance Manual, Chapter 24-00 (all series pre-600) and Chapter 24-01 (series 600). Pressure bung installations may be of the normal or reverse type assembly as defined in the Maintenance Manual reference noted in paragraph (c) of this AD. The total number may vary from one airplane to another depending on the electrical equipment installed.

(b) Gain access to the bungs in accordance with the procedures in the Maintenance Manual, Chapters 24 and 25.

(c) Inspect the bungs (both normal and reverse assemblies) for displacement and reinspect and/or rework as necessary in accordance with the instructions contained in Part B of temporary revision dated April 1, 1975, to HSA Maintenance Manual, Chapter 24-00 (all series except 600) and Chapter 24-01 (series 600), or the appropriate sections of the referenced chapters if the temporary revision has been incorporated into the HSA Maintenance Manual, or an FAA-approved equivalent.

(d) Where pressure bung(s) have been removed for rework, upon re-installation of the pressure bung(s) conduct a cabin leak rate check in accordance with the appropriate provisions of chapter 21 of the HSA Maintenance Manual prior to further flight to ensure the integrity of the pressure cabin.

This amendment becomes effective August 19, 1975.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_75-17-21.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
75-17-21
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes
Subject:
Cabin Pressurization
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/19/1975
Make:
Textron Aviation Inc.
Model:
BH.125 Series 400A | BH.125 Series 600A | DH.125 Series 1A | DH.125 Series 1A-522 | DH.125 Series 1A...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: 75-17-21
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2323

AD NUMBER:   75-17-21

SUBJECT HEADING:   Airworthiness Directives; HAWKER SIDDELEY AVIATION, LTD Models DH-125 and BH-125 Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective August 19, 1975.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-17-21 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2323. Applies to DH-125 and BH-125 airplanes certificated in all categories.

Compliance required as indicated.

To prevent possible rapid loss of cabin pressurization, accomplish the following:

Within 50 hours time in service after the effective date of this AD, unless already accomplished, inspect all Hellerman type cabin pressure seal bungs for displacement and rework as necessary in accordance with the following:

(a) Locate all Hellerman type cabin pressure seal bungs for the particular aircraft being inspected.

NOTE: Refer to the relevant aircraft wiring diagram manual (2 volumes) and to the maintenance practices in the Maintenance Manual, Chapter 24-00 (all series pre-600) and Chapter 24-01 (series 600). Pressure bung installations may be of the normal or reverse type assembly as defined in the Maintenance Manual reference noted in paragraph (c) of this AD. The total number may vary from one airplane to another depending on the electrical equipment installed.

(b) Gain access to the bungs in accordance with the procedures in the Maintenance Manual, Chapters 24 and 25.

(c) Inspect the bungs (both normal and reverse assemblies) for displacement and reinspect and/or rework as necessary in accordance with the instructions contained in Part B of temporary revision dated April 1, 1975, to HSA Maintenance Manual, Chapter 24-00 (all series except 600) and Chapter 24-01 (series 600), or the appropriate sections of the referenced chapters if the temporary revision has been incorporated into the HSA Maintenance Manual, or an FAA-approved equivalent.

(d) Where pressure bung(s) have been removed for rework, upon re-installation of the pressure bung(s) conduct a cabin leak rate check in accordance with the appropriate provisions of chapter 21 of the HSA Maintenance Manual prior to further flight to ensure the integrity of the pressure cabin.

This amendment becomes effective August 19, 1975.

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.