AD 90-26-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; BOEING Model 747-400 Series Airplanes |
Unsafe Condition
Failure of the fire detection warning system to annunciate a fire.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Modify the wiring of the aural and master warning indication systems of the fire detection system in accordance with Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990. An alternate means of compliance or adjustment of the compliance time may be used when approved by the FAA.
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Compliance Time
Within 45 days after the effective date of this airworthiness directive, unless previously accomplished.
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Affected Aircraft
Boeing Model 747-400 series airplanes listed in Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990, certificated in any category.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Fire Detection System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_90-26-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 90-26-08 Document Type: AD Final Rules Docket Number: 90-NM-252-AD Subject Heading: Airworthiness Directives; BOEING Model 747-400 Series Airplanes Subject: Fire Detection System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/26/1990 Make: The Boeing Company Model: 747-400 Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 90-26-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 90-NM-252-AD AMENDMENT: 39-6831 AD NUMBER: 90-26-08 SUBJECT HEADING: Airworthiness Directives; BOEING Model 747-400 Series Airplanes ACTION: SUMMARY: DATES: Effective December 26, 1990. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 90-26-08 BOEING: Amendment 39-6831. Docket No. 90-NM-252-AD. Applicability: Model 747-400 series airplanes, listed in Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990, certificated in any category. Compliance: Required within 45 days after the effective date of this airworthiness directive, unless previously accomplished. To prevent the failure of the fire detection warning system to annunciate a fire, accomplish the following: A. Modify the wiring of the aural and master warning indication systems of the fire detection system, in accordance with Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990. B. An alternate means 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 submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. 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. All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. This amendment (39-6831, AD 90-26-08) becomes effective on December 26, 1990. FOOTER:
Document Text
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AD Final Rules - DRS_90-26-08.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 90-26-08 Document Type: AD Final Rules Docket Number: 90-NM-252-AD Subject Heading: Airworthiness Directives; BOEING Model 747-400 Series Airplanes Subject: Fire Detection System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/26/1990 Make: The Boeing Company Model: 747-400 Series 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: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 90-26-08 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 90-NM-252-AD AMENDMENT: 39-6831 AD NUMBER: 90-26-08 SUBJECT HEADING: Airworthiness Directives; BOEING Model 747-400 Series Airplanes ACTION: SUMMARY: DATES: Effective December 26, 1990. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 90-26-08 BOEING: Amendment 39-6831. Docket No. 90-NM-252-AD. Applicability: Model 747-400 series airplanes, listed in Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990, certificated in any category. Compliance: Required within 45 days after the effective date of this airworthiness directive, unless previously accomplished. To prevent the failure of the fire detection warning system to annunciate a fire, accomplish the following: A. Modify the wiring of the aural and master warning indication systems of the fire detection system, in accordance with Boeing Alert Service Bulletin 747-26A2171, dated October 4, 1990. B. An alternate means 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 submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. 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. All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. This amendment (39-6831, AD 90-26-08) becomes effective on December 26, 1990. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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