AD 47-27-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | C54-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | C54A-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | C54B-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | C54D-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | C54E-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | C54G-DC | DOUGLAS Model C-54 and DC-4 Series Airplanes |
| aircraft | The Boeing Company | DC-4 | DOUGLAS Model C-54 and DC-4 Series Airplanes |
Unsafe Condition
Cracking failure of the collector ring 'Y' outlet assembly due to breathing of the exhaust stack, which induces failure creating a fire hazard.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Weld a scalloped stiffener flange on the exhaust collector aft of the 'Y' outlet assembly. Inspect for cracks immediately and at intervals not exceeding 50 hours of operation until the repair is completed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Not later than the first engine change subsequent to July 15, 1947, but in any event not later than October 15, 1947.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
All C-54 and DC-4 Series Airplanes having exhaust collector rings made up of top segments P/N 5174842-56 L.H. and 5174529-56 R.H.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Exhaust Collector Rings
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_47-27-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-27-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: DOUGLAS Model C-54 and DC-4 Series Airplanes Subject: Exhaust Collector Rings 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| C54B-DC | C54D-DC | C54E-DC | C54G-DC | DC-4 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 47-27-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-27-04 SUBJECT HEADING: DOUGLAS Model C-54 and DC-4 Series Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-27-04 DOUGLAS: (Was Mandatory Note 18 of AD-762-7.) Applies to All C-54 and DC-4 Series Airplanes Having Exhaust Collector Rings Made Up of Top Segments P/N 5174842-56 L.H. and 5174529-56 R.H. To be accomplished not later than the first engine change subsequent to July 15, 1947, but in any event not later than October 15, 1947. Several reports have been received of cracking failure of the collector ring "Y" outlet assembly due to breathing of the exhaust stack. This induces failure which creates a fire hazard. This type of exhaust collector "Y" is not reinforced with a flange and is shown on page 4, Douglas Service Bulletin No. DC-4 No. 31. To correct this condition weld a scalloped stiffener flange on the exhaust collector aft of the "Y" outlet assembly. (Douglas Service Bulletin No. DC-4 No. 68 covers this same subject.) Until this repair is accomplished, inspection for cracks should be made immediately and at periods not to exceed 50 hours of operation. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_47-27-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 47-27-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: DOUGLAS Model C-54 and DC-4 Series Airplanes Subject: Exhaust Collector Rings 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: 47-27-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 47-27-04 SUBJECT HEADING: DOUGLAS Model C-54 and DC-4 Series Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 47-27-04 DOUGLAS: (Was Mandatory Note 18 of AD-762-7.) Applies to All C-54 and DC-4 Series Airplanes Having Exhaust Collector Rings Made Up of Top Segments P/N 5174842-56 L.H. and 5174529-56 R.H. To be accomplished not later than the first engine change subsequent to July 15, 1947, but in any event not later than October 15, 1947. Several reports have been received of cracking failure of the collector ring "Y" outlet assembly due to breathing of the exhaust stack. This induces failure which creates a fire hazard. This type of exhaust collector "Y" is not reinforced with a flange and is shown on page 4, Douglas Service Bulletin No. DC-4 No. 31. To correct this condition weld a scalloped stiffener flange on the exhaust collector aft of the "Y" outlet assembly. (Douglas Service Bulletin No. DC-4 No. 68 covers this same subject.) Until this repair is accomplished, inspection for cracks should be made immediately and at periods not to exceed 50 hours of operation. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2023-10-02
final ruleAirworthiness Directives; Transport and Commuter Category Airplanes
Unsafe Condition: Radio altimeter anomalies that are undetected by the automation or pilot, particularly close to the ground (e.g., landing flare), could lead to loss of continued safe flight and landing. Additional...
2011-12-01
final ruleAirworthiness Directives; Koito Industries, Ltd., Seats and Seating Systems Approved Under Technical Standard Order (TSO) TSO-C39b, TSO-C39c, or TSO-C127a
Unsafe Condition: Seats and seating systems may not meet certain flammability, static strength, and dynamic strength criteria. Failure to meet static and dynamic strength criteria could result in injuries during eme...
93-14-12
final ruleAirworthiness Directives; ESSEX PB&R CORPORATION (formerly E.I. DuPont de Nemours and Company \\nIncorporated) PELS Model 4566M37B Crewmember Protective Breathing Equipment (PBE) Units
Unsafe Condition: Leakage of the PBE neck seal could compromise the crew's ability to combat an aircraft fire.
85-23-04
final ruleAirworthiness Directives; McDONNELL DOUGLAS DC-4 and C54-DC Series, and all C54 Military
Unsafe Condition: Loss of the elevator trim tab control in flight due to cracks in the left-hand and right-hand elevator trim tab spars at station 81.5.
