AD 48-52-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | DC-6 | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
| aircraft | The Boeing Company | DC-6A | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
| aircraft | The Boeing Company | DC-6B | Airworthiness Directives; DOUGLAS All DC-6 Aircraft |
Unsafe Condition
Failure of the power leads connection to the main bus through Burndy limiters, abrasion of generator and starter cables in the No. 4 nacelle, inadequate stainless steel ducting on heaters, nacelle fluids contacting exhaust piping, insufficient turbine oil drainage, improper CO2 bottle configuration for wing heaters, and inadequate ducting of combustion air blowers could lead to electrical failures, cable damage, heater malfunctions, fluid leaks, oil system issues, fire hazards, and ineffective fire suppression systems.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Revise power leads connection method using Burndy limiters, reroute generator and starter cables in No. 4 nacelle, install stainless steel combustion air intake ducting on heaters, revise wing heater exhaust outlets, install expansion turbine oil drains and filling drains, install ducting from heaters to nacelle/tail skin with stainless steel nacelle ducting, and reconfigure CO2 system by deleting wing heater CO2 bottles and integrating fuselage nose CO2 banks with the heater fire extinguisher system.
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Compliance Time
not later than June 1, 1949
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Affected Aircraft
The Boeing Company DC-6, DC-6A, DC-6B aircraft
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Connecting Power Leads
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-52-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-52-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS All DC-6 Aircraft Subject: Connecting Power Leads 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The Boeing Company Model: DC-6 | DC-6A | DC-6B Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-52-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-52-01 SUBJECT HEADING: Airworthiness Directives; DOUGLAS All DC-6 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-52-01 DOUGLAS: Applies to All DC-6 Aircraft. To be accomplished not later than June 1, 1949. 1. Revise method of connecting power leads to main bus through Burndy limiters. 2. Reroute generator and starter cables in No. 4 nacelle to eliminate possibility of abrasion of power cables. 3. Install stainless steel combustion air intake ducting on all heaters. 4. Revise wing heater exhaust outlets to preclude nacelle fluids contacting exhaust piping. 5. Install expansion turbine oil drain and filling drain. 6. Install ducting from the wing and tail heater combustion air blowers to the outside skin of the nacelles and tail section. Ducting within the nacelles to be of stainless steel. 7. Delete present wing heater 1.4 pounds CO2 bottles and eject the fuselage nose CO2 banks to either wing heater. CO2 to go into the heater deicing and combustion air and into the area surrounding the heaters. Controls for the new system to be grouped with and worked in the same sequence as the tail and cabin heater fire extinguisher system. (Douglas DC-6 Service Bulletins No. 220, revised February 18, 1948; 270, dated March 8, 1948; 231, revised January 19, 1948; 259, revised March 12, 1948; 255, revised February 26, 1948; 256, revised February 12, 1948; and 272, revised April 8, 1948; cover the above items consecutively.) FOOTER:
Document Text
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AD Final Rules - DRS_48-52-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-52-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; DOUGLAS All DC-6 Aircraft Subject: Connecting Power Leads 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: 48-52-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-52-01 SUBJECT HEADING: Airworthiness Directives; DOUGLAS All DC-6 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-52-01 DOUGLAS: Applies to All DC-6 Aircraft. To be accomplished not later than June 1, 1949. 1. Revise method of connecting power leads to main bus through Burndy limiters. 2. Reroute generator and starter cables in No. 4 nacelle to eliminate possibility of abrasion of power cables. 3. Install stainless steel combustion air intake ducting on all heaters. 4. Revise wing heater exhaust outlets to preclude nacelle fluids contacting exhaust piping. 5. Install expansion turbine oil drain and filling drain. 6. Install ducting from the wing and tail heater combustion air blowers to the outside skin of the nacelles and tail section. Ducting within the nacelles to be of stainless steel. 7. Delete present wing heater 1.4 pounds CO2 bottles and eject the fuselage nose CO2 banks to either wing heater. CO2 to go into the heater deicing and combustion air and into the area surrounding the heaters. Controls for the new system to be grouped with and worked in the same sequence as the tail and cabin heater fire extinguisher system. (Douglas DC-6 Service Bulletins No. 220, revised February 18, 1948; 270, dated March 8, 1948; 231, revised January 19, 1948; 259, revised March 12, 1948; 255, revised February 26, 1948; 256, revised February 12, 1948; and 272, revised April 8, 1948; cover the above items consecutively.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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