AD 52-20-01

final rule

Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft

AD Number
52-20-01
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of an aircraft electrical generator and wiring assembly
Problem area Electrical system

Applicability

TypeManufacturerModelDetails
aircraft The Boeing Company DC-6 Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft
aircraft The Boeing Company DC-6A Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft
aircraft The Boeing Company DC-6B Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft

Unsafe Condition

Overvoltage in the Eclipse Generator System and General Electrical Generator System could lead to electrical fire and loss of essential electrical and electronic equipment necessary for continued flight.

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

Required Actions

Replace B-14 generator contactors with 120-volt rated high-voltage contactors in the Eclipse system. Install overvoltage relays and either replace G.E. P/N 3GTR-77A102 relays with 120-volt rated relays or rework G.E. P/N XRP-12 circuit breakers to trip with the generator control relay in the General Electric system.

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

Compliance Time

as soon as practicable, but not later than February 1, 1954

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

Affected Aircraft

Douglas Models DC-6, DC-6A, DC-6B aircraft below serial number 43274

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

Federal Register Abstract

Overvoltage Protection

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_52-20-01.html
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AD Number:
52-20-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft
Subject:
Overvoltage Protection
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Superseded AD: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Superseded By: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: 52-20-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   52-20-01

SUBJECT HEADING:   Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
52-20-01 DOUGLAS: Applies to Models DC-6, DC-6A, DC-6B Aircraft Below Serial Number 43274.

To be accomplished as soon as practicable, but not later than February 1, 1954.

To reduce the likelihood of electrical fire and the loss of electrical and electronic equipment essential to continue flight, it is necessary to provide adequate overvoltage protection. There are two systems involved, known as the "Eclipse Generator System" and the "General Electrical Generator System". The changes required in each of these systems are as follows:

Eclipse. Replace the four B-14 type generator contactors with a high-voltage (120-volt rating) contactors of sufficient capacity to interrupt an overvoltage generator. Overvoltage relays are already installed in the Eclipse system, and these should be retained.

General Electric. Install overvoltage sensing relays and either (1) replace the four generator control relays, G.E. P/N 3GTR-77A102, with a high-voltage (120-volt rating) relay of sufficient capacity to interrupt an overvoltage generator, or (2) rework the G.E. P/N XRP-12 reverses current circuit breakers so as to trip out simultaneously with the generator control relay to provide for necessary additional interruption capacity. Except for the General Electric alternate (2) fix, this same subject is described in Douglas Service Bulletin DC-6 No. 470. The General Electric Co. has service information available for the G.E. system alternate (2) rework.


FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_52-20-01.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
52-20-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft
Subject:
Overvoltage Protection
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: 52-20-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   52-20-01

SUBJECT HEADING:   Airworthiness Directives; DOUGLAS Models DC-6, DC-6A, DC-6B Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
52-20-01 DOUGLAS: Applies to Models DC-6, DC-6A, DC-6B Aircraft Below Serial Number 43274.

To be accomplished as soon as practicable, but not later than February 1, 1954.

To reduce the likelihood of electrical fire and the loss of electrical and electronic equipment essential to continue flight, it is necessary to provide adequate overvoltage protection. There are two systems involved, known as the "Eclipse Generator System" and the "General Electrical Generator System". The changes required in each of these systems are as follows:

Eclipse. Replace the four B-14 type generator contactors with a high-voltage (120-volt rating) contactors of sufficient capacity to interrupt an overvoltage generator. Overvoltage relays are already installed in the Eclipse system, and these should be retained.

General Electric. Install overvoltage sensing relays and either (1) replace the four generator control relays, G.E. P/N 3GTR-77A102, with a high-voltage (120-volt rating) relay of sufficient capacity to interrupt an overvoltage generator, or (2) rework the G.E. P/N XRP-12 reverses current circuit breakers so as to trip out simultaneously with the generator control relay to provide for necessary additional interruption capacity. Except for the General Electric alternate (2) fix, this same subject is described in Douglas Service Bulletin DC-6 No. 470. The General Electric Co. has service information available for the G.E. system alternate (2) rework.


FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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