AD 47-12-02

final rule

DOUGLAS Model DC-4 and C-54 Series Airplanes

AD Number
47-12-02
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft The Boeing Company C54-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company C54A-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company C54B-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company C54D-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company C54E-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company C54G-DC DOUGLAS Model DC-4 and C-54 Series Airplanes
aircraft The Boeing Company DC-4 DOUGLAS Model DC-4 and C-54 Series Airplanes

Unsafe Condition

Center main bearing failures have occurred in Pratt & Whitney R-2000-11 engines, specifically involving roller bearing P/N 24966 and plain bearings P/N 97387 and 97387B.

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

Required Actions

Remove plain type center main bearings (P/N 97387 and 97387B) from service by July 15, 1947. Install superinspected roller bearings (P/N 24966) or incorporate 2SD13-G or equivalent main components of the power section crankcase. Conduct main oil screen checks at each routine inspection or every 75 hours of operation until modifications are complete.

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

Compliance Time

not later than July 15, 1947

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

Affected Aircraft

Douglas Model DC-4 and C-54 Series airplanes equipped with Pratt & Whitney R-2000-11 engines

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

Federal Register Abstract

Center Main Bearings

Applicability Source Text

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AD Number:
47-12-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
DOUGLAS Model DC-4 and C-54 Series Airplanes
Subject:
Center Main Bearings
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
The Boeing Company
Model:
C54-DC | C54A-DC | C54B-DC | C54D-DC | C54E-DC | C54G-DC | DC-4
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Superseded AD: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: 47-12-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-12-02

SUBJECT HEADING:   DOUGLAS Model DC-4 and C-54 Series Airplanes

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
47-12-02 DOUGLAS: (Was Mandatory Note 15 of AD-762-7.) Applies Only to DC-4 and C-54 Series Airplanes Equipped With Pratt & Whitney R-2000-11 Engines.

To be accomplished not later than July 15, 1947.

A considerable number of center main bearing failures have occurred in the R-2000-11 engine. These failures include roller bearing P/N 24966 and plain bearing P/N 97387 and 97387B.

To remedy this unsatisfactory condition as soon as possible, the following shall be accomplished:

Remove from service at the first opportunity, but in no case later than July 15, 1947, all plain type center main bearings of the above part numbers. Install either the superinspected roller bearing (same part number as above) or incorporate the 2SD13-G or equivalent type main components of the power section crankcase, details of which can be obtained from Pratt & Whitney instructions dated January 15, 1947 and entitled "Power Section Service Fix for R-2000-7 and R-2000-11 Engines". Superinspected roller bearings may be procured through Pratt & Whitney or bearings in stock may become eligible if they are disassembled, inspected, and the inner race magnafluxed.

In cases where operating specifications do not so provide, main oil screen (on right side of rear accessory housing) checks will be accomplished at each routine inspection or at least at every 75 hours of operation to detect failure of bearing. This precautionary inspection must be conducted immediately and also after change to the superinspected roller bearing. However, this precautionary inspection is waived after complete modification has been accomplished to the 2SD13-G or equivalent type components in view of the greatly improved reliability and durability which these components have demonstrated in comparable service.


FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_47-12-02.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
47-12-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
DOUGLAS Model DC-4 and C-54 Series Airplanes
Subject:
Center Main Bearings
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
The Boeing Company
Model:
C54-DC | C54A-DC | C54B-DC | C54D-DC | C54E-DC | C54G-DC | DC-4
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: 47-12-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   47-12-02

SUBJECT HEADING:   DOUGLAS Model DC-4 and C-54 Series Airplanes

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
47-12-02 DOUGLAS: (Was Mandatory Note 15 of AD-762-7.) Applies Only to DC-4 and C-54 Series Airplanes Equipped With Pratt & Whitney R-2000-11 Engines.

To be accomplished not later than July 15, 1947.

A considerable number of center main bearing failures have occurred in the R-2000-11 engine. These failures include roller bearing P/N 24966 and plain bearing P/N 97387 and 97387B.

To remedy this unsatisfactory condition as soon as possible, the following shall be accomplished:

Remove from service at the first opportunity, but in no case later than July 15, 1947, all plain type center main bearings of the above part numbers. Install either the superinspected roller bearing (same part number as above) or incorporate the 2SD13-G or equivalent type main components of the power section crankcase, details of which can be obtained from Pratt & Whitney instructions dated January 15, 1947 and entitled "Power Section Service Fix for R-2000-7 and R-2000-11 Engines". Superinspected roller bearings may be procured through Pratt & Whitney or bearings in stock may become eligible if they are disassembled, inspected, and the inner race magnafluxed.

In cases where operating specifications do not so provide, main oil screen (on right side of rear accessory housing) checks will be accomplished at each routine inspection or at least at every 75 hours of operation to detect failure of bearing. This precautionary inspection must be conducted immediately and also after change to the superinspected roller bearing. However, this precautionary inspection is waived after complete modification has been accomplished to the 2SD13-G or equivalent type components in view of the greatly improved reliability and durability which these components have demonstrated in comparable service.


FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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