AD 47-12-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| 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.
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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.
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Compliance Time
not later than July 15, 1947
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Affected Aircraft
Douglas Model DC-4 and C-54 Series airplanes equipped with Pratt & Whitney R-2000-11 engines
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Federal Register Abstract
Center Main Bearings
Applicability Source Text
Show captured applicability text from the source AD
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| C54B-DC | C54D-DC | C54E-DC | C54G-DC | DC-4 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-12-02 CITATION: This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:
Document Text
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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:
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Retrieved: Apr 8, 2026
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