AD 91-20-06

final rule

Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes

AD Number
91-20-06
Status
final_rule
Effective Date
Product Category
aircraft
Docket
91-NM-56-AD
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft The Boeing Company 747-100 Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
aircraft The Boeing Company 747-100B Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
aircraft The Boeing Company 747-100B SUD Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
aircraft The Boeing Company 747-200B Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
aircraft The Boeing Company 747-200C Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
aircraft The Boeing Company 747-200F Series Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes

Unsafe Condition

Cross connection of the engine nacelle fire extinguishing plumbing during maintenance could lead to failure of the fire extinguishing system to function properly.

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

Required Actions

Conduct an inspection of the engine fire extinguishing system plumbing within 10 days after October 24, 1989, and after any maintenance that could cause mis-plumbing, following Boeing SB 747-26A2094, Rev 1. Correct discrepancies before further flight. Modify the system plumbing within 18 months after November 7, 1991, per Boeing SB 747-26-2162 to terminate repetitive inspections.

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

Compliance Time

Within 10 days after October 24, 1989; within 18 months after November 7, 1991

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

Affected Aircraft

Boeing Model 747-100 and -200 series airplanes manufactured prior to January 1, 1981, equipped with GE CF6-45/50 or Pratt & Whitney JT9D-70 engines, as listed in Boeing SB 747-26-2162.

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

Federal Register Abstract

Engine Fire Extinguishing System

Applicability Source Text

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AD Number:
91-20-06
Document Type:
AD Final Rules
Docket Number:
91-NM-56-AD
Subject Heading:
Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
Subject:
Engine Fire Extinguishing System
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
11/07/1991
Make:
The Boeing Company
Model:
747-100 Series | 747-100B Series | 747-100B SUD Series | 747-200B Series | 747-200C Series | 747-200...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: 91-20-06
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-NM-56-AD

AMENDMENT:   39-8040

AD NUMBER:   91-20-06

SUBJECT HEADING:   Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective November 7, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-20-06 BOEING: Amendment 39-8040. Docket 91-NM-56-AD. Supersedes AD 89-22-03.

Applicability: Model 747-100 and -200 series airplanes, manufactured prior to January 1, 1981; equipped with General Electric CF6-45/50 or Pratt and Whitney JT9D-70 engines; as listed in Boeing Service Bulletin 747-26-2162, dated September 20, 1990, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To preclude cross connection of the engine nacelle fire extinguishing plumbing during maintenance, accomplish the following:

A. Within 10 days after October 24, 1989 (the effective date of Amendment 39- 6353, AD 89-22-03), and thereafter, immediately following any maintenance action which could cause mis-plumbing, conduct an inspection of the engine fire extinguishing system plumbing in accordance with Boeing Service Bulletin 747-26A2094, Revision 1, dated March 25, 1983.

B. Before further flight, correct any discrepancy detected during the functional tests required by paragraph A. of this AD.

C. Within 18 months after the effective date of this amendment, modify the engine fire extinguisher system plumbing in accordance with Boeing Service Bulletin 747-26-2162, dated September 20, 1990. Accomplishment of this modification constitutes terminating action for the repetitive inspections required by paragraph A. of this AD.

D. 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, Seattle Aircraft Certification Office (ACO), 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, Seattle ACO.

E. 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.

F. The modification shall be done in accordance with Boeing Service Bulletin 747- 26-2162, dated September 20, 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington, or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C.

Airworthiness Directive 91-20-06 supersedes AD 89-22-03, Amendment 39-6353.
This amendment (39-8040, AD 91-20-06) becomes effective on November 7, 1991.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_91-20-06.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
91-20-06
Document Type:
AD Final Rules
Docket Number:
91-NM-56-AD
Subject Heading:
Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes
Subject:
Engine Fire Extinguishing System
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
11/07/1991
Make:
The Boeing Company
Model:
747-100 Series | 747-100B Series | 747-100B SUD Series | 747-200B Series | 747-200C Series | 747-200...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: 91-20-06
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-NM-56-AD

AMENDMENT:   39-8040

AD NUMBER:   91-20-06

SUBJECT HEADING:   Airworthiness Directives; BOEING Model 747-100 and -200 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective November 7, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-20-06 BOEING: Amendment 39-8040. Docket 91-NM-56-AD. Supersedes AD 89-22-03.

Applicability: Model 747-100 and -200 series airplanes, manufactured prior to January 1, 1981; equipped with General Electric CF6-45/50 or Pratt and Whitney JT9D-70 engines; as listed in Boeing Service Bulletin 747-26-2162, dated September 20, 1990, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To preclude cross connection of the engine nacelle fire extinguishing plumbing during maintenance, accomplish the following:

A. Within 10 days after October 24, 1989 (the effective date of Amendment 39- 6353, AD 89-22-03), and thereafter, immediately following any maintenance action which could cause mis-plumbing, conduct an inspection of the engine fire extinguishing system plumbing in accordance with Boeing Service Bulletin 747-26A2094, Revision 1, dated March 25, 1983.

B. Before further flight, correct any discrepancy detected during the functional tests required by paragraph A. of this AD.

C. Within 18 months after the effective date of this amendment, modify the engine fire extinguisher system plumbing in accordance with Boeing Service Bulletin 747-26-2162, dated September 20, 1990. Accomplishment of this modification constitutes terminating action for the repetitive inspections required by paragraph A. of this AD.

D. 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, Seattle Aircraft Certification Office (ACO), 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, Seattle ACO.

E. 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.

F. The modification shall be done in accordance with Boeing Service Bulletin 747- 26-2162, dated September 20, 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington, or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C.

Airworthiness Directive 91-20-06 supersedes AD 89-22-03, Amendment 39-6353.
This amendment (39-8040, AD 91-20-06) becomes effective on November 7, 1991.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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