AD 91-14-12

final rule

BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes

AD Number
91-14-12
Status
final_rule
Effective Date
Product Category
aircraft
Docket
91-NM-44-AD
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Textron Aviation Inc. BH.125 Series 600A BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes
aircraft Textron Aviation Inc. HS.125 Series 600A BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes
aircraft Textron Aviation Inc. HS.125 Series 700A BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes

Unsafe Condition

Loss of the standby constant frequency power system which provides the necessary back-up capability when the primary power system fails.

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

Required Actions

Install a partial cover above the standby inverter 'TF' located between frames 22 and 23 LH if the converter is installed as depicted on pages 5-6 of the service bulletin. Compliance must be in accordance with British Aerospace Service Bulletin 24-279-3255A dated November 16, 1990.

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

Compliance Time

within 160 days after the effective date of this AD, unless previously accomplished

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

Affected Aircraft

Model HS.125-600A and BH.125-600A series airplanes (Post Modification 252475) and Model HS.125-700A series airplanes (Post Modification 252509)

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

Federal Register Abstract

Power System

Applicability Source Text

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AD Number:
91-14-12
Document Type:
AD Final Rules
Docket Number:
91-NM-44-AD
Subject Heading:
BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes
Subject:
Power System
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/06/1991
Make:
Textron Aviation Inc.
Model:
BH.125 Series 600A | HS.125 Series 600A | HS.125 Series 700A
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Superseded AD: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Superseded By: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: 91-14-12
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-NM-44-AD

AMENDMENT:   39-7053

AD NUMBER:   91-14-12

SUBJECT HEADING:   BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective August 6, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-14-12 BRITISH AEROSPACE: Amendment 39-7053. Docket No. 91-NM-44-AD.

Applicability: Model HS.125-600A and BH.125-600A series airplanes (Post Modification 252475) and Model HS.125-700A series airplanes (Post Modification 252509); as listed in British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990; certificated in any category.

Compliance: Required within 160 days after the effective date of this AD, unless previously accomplished.

To prevent loss of the standby constant frequency power system which provides the necessary back-up capability when the primary power system fails, accomplish the following:

A. Install a partial cover above the standby inverter "TF" located between frames 22 and 23 LH if the converter is installed as depicted on pages 5-6 of the service bulletin, in accordance with British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990.

B. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Standardization Branch.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

D. The installation requirements shall be done in accordance with British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041. Copies may be inspected at the FAA, Transport Airplane Directorate, Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

This amendment (39-7053, AD 91-14-12) becomes effective on August 6, 1991.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_91-14-12.html
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Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
91-14-12
Document Type:
AD Final Rules
Docket Number:
91-NM-44-AD
Subject Heading:
BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes
Subject:
Power System
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/06/1991
Make:
Textron Aviation Inc.
Model:
BH.125 Series 600A | HS.125 Series 600A | HS.125 Series 700A
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: 91-14-12
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-NM-44-AD

AMENDMENT:   39-7053

AD NUMBER:   91-14-12

SUBJECT HEADING:   BRITISH AEROSPACE Model HS.125-600A, BH.125-600A and HS.125-700A Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective August 6, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-14-12 BRITISH AEROSPACE: Amendment 39-7053. Docket No. 91-NM-44-AD.

Applicability: Model HS.125-600A and BH.125-600A series airplanes (Post Modification 252475) and Model HS.125-700A series airplanes (Post Modification 252509); as listed in British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990; certificated in any category.

Compliance: Required within 160 days after the effective date of this AD, unless previously accomplished.

To prevent loss of the standby constant frequency power system which provides the necessary back-up capability when the primary power system fails, accomplish the following:

A. Install a partial cover above the standby inverter "TF" located between frames 22 and 23 LH if the converter is installed as depicted on pages 5-6 of the service bulletin, in accordance with British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990.

B. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Standardization Branch.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

D. The installation requirements shall be done in accordance with British Aerospace Service Bulletin 24-279-3255A, dated November 16, 1990. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041. Copies may be inspected at the FAA, Transport Airplane Directorate, Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

This amendment (39-7053, AD 91-14-12) becomes effective on August 6, 1991.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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