AD 49-18-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46A | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46D | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46F | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46R | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46E | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | C-46/CW20-T | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
| aircraft | Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation | Super C-46/CW20-T | Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes |
Unsafe Condition
Combustion heater fire protection deficiencies, including inadequate exhaust pipe shrouds, un-drained combustion chambers, non-fireproof drain lines with traps, unshielded fuel components, insufficient thermal overheat protection, lack of manual fuel shutoff valves, inadequate fire extinguisher/detector installations, and insufficient emergency procedures in the Airplane Flight Manual.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install fireproof shrouds around heater exhaust pipes, drain combustion chambers to exterior with fireproof lines without traps, enclose fuel components in fuel/fume proof ventilated enclosures drained externally, rig thermal overheat switches to shut off fuel/ignition and prevent automatic recycling, install manual fuel shutoff valves, provide fire extinguishers/detectors with specific placement and CO2 requirements, and revise AFM with emergency procedures.
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Compliance Time
Not later than the dates specified in Sections 41.20(f), 61.30 and Amendment 42-8 as revised by Special Civil Air Regulation No. 329 and any subsequent regulations affecting these compliance dates.
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Affected Aircraft
Curtiss-Wright Models of C-46 Series airplanes used in passenger operation under Part 41, 42, or 61 of the Civil Air Regulations, including models C-46A, C-46D, C-46F, C-46R, C-46E, C-46/CW20-T, and Super C-46/CW20-T.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Combustion Heater Fire Protection
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_49-18-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 49-18-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes Subject: Combustion Heater Fire Protection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Air...Show more Model: C-46A | C-46D | C-46F | C-46R | C-46E | C-46/CW20-T | Super C-46/CW20-T 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: 49-18-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 49-18-01 SUBJECT HEADING: Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 49-18-01 CURTISS-WRIGHT Applies to all Models of C-46 Series airplanes used in passenger operation under provisions of Part 41, 42, or 61 of the Civil Air Regulations as specified in Sections 41.20 (f), 61.30 and Amendment 42-8. To be accomplished not later than the dates specified in above amendments as revised by Special Civil Air Regulation No. 329 and any subsequent regulations affecting these compliance dates. (This AD pertains only to combustion heater fire protection aspects of the above Regulation Amendments. Separate AD's will be issued covering fire protection for the powerplant installation and for the baggage and cargo compartments of the airplane). (1) Each heater exhaust pipe shall be completely enclosed with well-ventilated, fireproof shrouds. (2) Each heater combustion chamber shall be drained to the exterior of the airplane. All such drain lines shall be of fireproof construction and contain no traps in the normal flight or ground attitudes. (3) The heater fuel components presently mounted on top of each heater shall be located in fuel and fume proof enclosures, ventilated and drained to the exterior of the airplane. (4) The thermal overheat switches for each heater shall be rigged to shut off the fuel supply and ignition circuits of the heaters when overheating occurs. These switches must also be arranged so as to prevent their automatically recycling to "ON" once overheating has occurred. The present overheat switches are not intended to be used as cycling switches. In cycling to produce the required heat is necessary, it must be accomplished at a lower temperature by an additional cycling switch controlling a cycling solenoid. (5) A manual fuel shutoff valve shall be provided. (USAF Technical Order 01- 25LA-211 describes such an installation.) (6) Adequate fire extinguisher and fire detector installations shall be provided for each heater. The fire detector installation shall contain at least one detector centrally located over the heaters in the heater area and one detector in the ventilating air duct of each heater just aft of the combustion chamber. The fire extinguisher system should provide at least 1 pound of carbon dioxide for each heater directed into the inlet side of the ventilating air stream. Instructions for operating this carbon dioxide system should also require that the ventilating air duct valve be closed when carbon dioxide is injected to the heater. With the arrangement as described, no flight tests of carbon dioxide contamination of the pilots compartment or cabin area need be conducted. As outlined in the Airworthiness Directive concerning fire protection for the baggage and cargo compartments, however, flight tests to establish smoke evacuation procedures for the cargo compartments when these compartments are carrying cargo, will need to be accomplished. The results of these tests will determine the procedure to be followed to rid the airplane of noxious gases. (7) Revision pages for the Airplane Flight Manual must be prepared to cover emergency fire procedures as well as smoke and other noxious gas elimination procedures. FOOTER:
Document Text
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AD Final Rules - DRS_49-18-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 49-18-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes Subject: Combustion Heater Fire Protection Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Air...Show more Model: C-46A | C-46D | C-46F | C-46R | C-46E | C-46/CW20-T | Super C-46/CW20-T 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: 49-18-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 49-18-01 SUBJECT HEADING: Airworthiness Directives; CURTISS-WRIGHT Models of C-46 Series Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 49-18-01 CURTISS-WRIGHT Applies to all Models of C-46 Series airplanes used in passenger operation under provisions of Part 41, 42, or 61 of the Civil Air Regulations as specified in Sections 41.20 (f), 61.30 and Amendment 42-8. To be accomplished not later than the dates specified in above amendments as revised by Special Civil Air Regulation No. 329 and any subsequent regulations affecting these compliance dates. (This AD pertains only to combustion heater fire protection aspects of the above Regulation Amendments. Separate AD's will be issued covering fire protection for the powerplant installation and for the baggage and cargo compartments of the airplane). (1) Each heater exhaust pipe shall be completely enclosed with well-ventilated, fireproof shrouds. (2) Each heater combustion chamber shall be drained to the exterior of the airplane. All such drain lines shall be of fireproof construction and contain no traps in the normal flight or ground attitudes. (3) The heater fuel components presently mounted on top of each heater shall be located in fuel and fume proof enclosures, ventilated and drained to the exterior of the airplane. (4) The thermal overheat switches for each heater shall be rigged to shut off the fuel supply and ignition circuits of the heaters when overheating occurs. These switches must also be arranged so as to prevent their automatically recycling to "ON" once overheating has occurred. The present overheat switches are not intended to be used as cycling switches. In cycling to produce the required heat is necessary, it must be accomplished at a lower temperature by an additional cycling switch controlling a cycling solenoid. (5) A manual fuel shutoff valve shall be provided. (USAF Technical Order 01- 25LA-211 describes such an installation.) (6) Adequate fire extinguisher and fire detector installations shall be provided for each heater. The fire detector installation shall contain at least one detector centrally located over the heaters in the heater area and one detector in the ventilating air duct of each heater just aft of the combustion chamber. The fire extinguisher system should provide at least 1 pound of carbon dioxide for each heater directed into the inlet side of the ventilating air stream. Instructions for operating this carbon dioxide system should also require that the ventilating air duct valve be closed when carbon dioxide is injected to the heater. With the arrangement as described, no flight tests of carbon dioxide contamination of the pilots compartment or cabin area need be conducted. As outlined in the Airworthiness Directive concerning fire protection for the baggage and cargo compartments, however, flight tests to establish smoke evacuation procedures for the cargo compartments when these compartments are carrying cargo, will need to be accomplished. The results of these tests will determine the procedure to be followed to rid the airplane of noxious gases. (7) Revision pages for the Airplane Flight Manual must be prepared to cover emergency fire procedures as well as smoke and other noxious gas elimination procedures. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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