AD 48-49-03
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | DC-6 | Airworthiness Directives; DOUGLAS All DC-6 Airplanes |
| aircraft | The Boeing Company | DC-6A | Airworthiness Directives; DOUGLAS All DC-6 Airplanes |
| aircraft | The Boeing Company | DC-6B | Airworthiness Directives; DOUGLAS All DC-6 Airplanes |
Unsafe Condition
Some essential electrical circuits were inadvertently connected to the distribution bus instead of the master bus, increasing the risk of loss of power for circuits critical in flight.
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Required Actions
Inspect all DC-6 aircraft to ensure specified circuit protectors (Radio Master, Fuel Booster Pumps, Inverter Power, Propeller Booster, Propeller Control, Propeller Synchronizer, Governor Control, Generator Control Panel) are connected to the master bus. Rewire as necessary per Douglas Service Bulletin DC-6 No. 329.
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Compliance Time
not later than March 1, 1949
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Affected Aircraft
The Boeing Company DC-6, DC-6A, DC-6B airplanes
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Federal Register Abstract
Electrical Circuit Inspection
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-49-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-49-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS All DC-6 Airplanes Subject: Electrical Circuit Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: The Boeing Company Model: DC-6 | DC-6A | DC-6B Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-49-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-49-03 SUBJECT HEADING: Airworthiness Directives; DOUGLAS All DC-6 Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-49-03 DOUGLAS: Applies to All DC-6 Airplanes. Compliance required not later than March 1, 1949. To reduce the probability of a loss of power for electrical circuits considered to be essential in flight, these essential circuits were designed to be connected directly to the master bus. Other less essential circuits are connected to the master bus through a 500-ampere Burndy limiter (fuse). In an undetermined number of aircraft some of the essential circuits were inadvertently connected to the distribution bus rather than to the master bus. It is necessary, therefore, that all DC-6 aircraft be inspected and such rewiring as necessary be done to assure that the following circuit protectors are connected to the master bus: Radio Master (B1-102), Fuel Booster Pumps (B1-63, 97), Invertor Power (B1-111, 116), Propeller Booster (Curtiss Propellers only, F1-28, 29), Propeller Control (Curtiss: B1-141, 142, 143, 144. Hamilton Standard: B1-188, 189, 190, 191), Propeller Synchronizer (B1-145), Governor Control (Hamilton Standard only, B1-192), Generator Control Panel (Eclipse Generator System only, B1-246, 247, 248, 249. Reference Douglas Service Bulletin DC-6 No. 329. (Douglas Service Letter A214-T.3338/TFW dated October 22, 1948 covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_48-49-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-49-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS All DC-6 Airplanes Subject: Electrical Circuit Inspection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: The Boeing Company Model: DC-6 | DC-6A | DC-6B 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: 48-49-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-49-03 SUBJECT HEADING: Airworthiness Directives; DOUGLAS All DC-6 Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-49-03 DOUGLAS: Applies to All DC-6 Airplanes. Compliance required not later than March 1, 1949. To reduce the probability of a loss of power for electrical circuits considered to be essential in flight, these essential circuits were designed to be connected directly to the master bus. Other less essential circuits are connected to the master bus through a 500-ampere Burndy limiter (fuse). In an undetermined number of aircraft some of the essential circuits were inadvertently connected to the distribution bus rather than to the master bus. It is necessary, therefore, that all DC-6 aircraft be inspected and such rewiring as necessary be done to assure that the following circuit protectors are connected to the master bus: Radio Master (B1-102), Fuel Booster Pumps (B1-63, 97), Invertor Power (B1-111, 116), Propeller Booster (Curtiss Propellers only, F1-28, 29), Propeller Control (Curtiss: B1-141, 142, 143, 144. Hamilton Standard: B1-188, 189, 190, 191), Propeller Synchronizer (B1-145), Governor Control (Hamilton Standard only, B1-192), Generator Control Panel (Eclipse Generator System only, B1-246, 247, 248, 249. Reference Douglas Service Bulletin DC-6 No. 329. (Douglas Service Letter A214-T.3338/TFW dated October 22, 1948 covers this same subject.) FOOTER:
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Retrieved: Apr 8, 2026
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