AD 48-09-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | C54-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54A-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54B-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54D-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54E-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | C54G-DC | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
| aircraft | The Boeing Company | DC-4 | Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft |
Unsafe Condition
Short circuits in the electrical distribution bus from nacelles one to four, which cannot be protected by circuit protective devices.
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Required Actions
Inspect the bus for 1/2-inch clearance from protuberances in nacelle areas, replace substandard brackets and clamps with approved Douglas standard quality and Adel or equivalent cushioned nongrounding type, inspect and replace No. 1/0 nacelle-to-bus feeder cables if chafing or mechanical deterioration is evident.
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Compliance Time
Inspection required by April 1, 1948, and thereafter at intervals not to exceed 400 hours (or at each routine check period for scheduled air carrier operators); inspection required not later than July 1, 1948, and thereafter at intervals not to exceed 8,000 hours; and determine compliance by June 1, 1948.
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Affected Aircraft
Douglas C-54 and DC-4 Aircraft, including models C54-DC, C54A-DC, C54B-DC, C54D-DC, C54E-DC, C54G-DC, and DC-4.
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Federal Register Abstract
Electrical Distribution Bus
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-09-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-09-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft Subject: Electrical Distribution Bus 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: 48-09-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-09-02 SUBJECT HEADING: Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-09-02 DOUGLAS: Applies to C-54 and DC-4 Aircraft. To preclude the probability of short circuits occurring in the electrical distribution bus which runs from nacelles number one to four, and which is impracticable to protect by circuit protective devices, the following must be accomplished to assure that this bus will be in a fault-free condition. I. Inspection required by April 1, 1948, and thereafter at intervals not to exceed 400 hours (or in the case of scheduled air carrier operators at each routine check period.) Determine that at least 1/2-inch clearance is maintained between the bus and protuberances likely to "ground" the bus in the nacelle areas. Note particularly this clearance at the engine control pulleys and the pulley guide brackets. II. Inspection required not later than July 1, 1948, and thereafter at intervals not to exceed 8,000 hours. In those installations where the large No. 1/0 nacelle-to-bus feeder cables are run in metallic conduit, such cables must be pulled out for inspection. Replace by new cable ANA Spec. ANJC48a or Douglas DES SM-2001, where chafing or mechanical deterioration of the insulation is evident. (NOTE: Oil-soaked insulation alone is not considered as sufficient cause to require the replacement of this cable.) III. Not later than June 1, 1948. Determine that the bus supporting brackets are of approved Douglas Aircraft Co. standard quality and that Adel or equivalent cushioned nongrounding type bus clamps are used for clamping the bus onto the brackets. Any substandard brackets and clamps must be replaced. (Douglas Service Letter No. A214TS-1245/SRD-530 dated October 10, 1947, covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_48-09-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-09-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft Subject: Electrical Distribution Bus 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: 48-09-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-09-02 SUBJECT HEADING: Airworthiness Directives; DOUGLAS C-54 and DC-4 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-09-02 DOUGLAS: Applies to C-54 and DC-4 Aircraft. To preclude the probability of short circuits occurring in the electrical distribution bus which runs from nacelles number one to four, and which is impracticable to protect by circuit protective devices, the following must be accomplished to assure that this bus will be in a fault-free condition. I. Inspection required by April 1, 1948, and thereafter at intervals not to exceed 400 hours (or in the case of scheduled air carrier operators at each routine check period.) Determine that at least 1/2-inch clearance is maintained between the bus and protuberances likely to "ground" the bus in the nacelle areas. Note particularly this clearance at the engine control pulleys and the pulley guide brackets. II. Inspection required not later than July 1, 1948, and thereafter at intervals not to exceed 8,000 hours. In those installations where the large No. 1/0 nacelle-to-bus feeder cables are run in metallic conduit, such cables must be pulled out for inspection. Replace by new cable ANA Spec. ANJC48a or Douglas DES SM-2001, where chafing or mechanical deterioration of the insulation is evident. (NOTE: Oil-soaked insulation alone is not considered as sufficient cause to require the replacement of this cable.) III. Not later than June 1, 1948. Determine that the bus supporting brackets are of approved Douglas Aircraft Co. standard quality and that Adel or equivalent cushioned nongrounding type bus clamps are used for clamping the bus onto the brackets. Any substandard brackets and clamps must be replaced. (Douglas Service Letter No. A214TS-1245/SRD-530 dated October 10, 1947, covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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