AD 57-05-01
final rule
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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
| 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 | CURTISS-WRIGHT Model C-46 Series Aircraft |
Unsafe Condition
Hydraulic dump valves venting fluid directly overboard on the inboard side of the nacelles directly aft of the exhaust stack can result in fires in areas without fire detection or protection.
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Required Actions
Reroute the vent line to the nacelle tail cone per Curtiss-Wright Service Bulletin C-46 1226 or Drawing No. 20-575-3206, reroute to return to the main system per change A of T.O. 01-25LA-209, or reroute to an approved equivalent configuration.
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Compliance Time
August 1, 1957
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Affected Aircraft
Curtiss-Wright Model C-46 Series aircraft including C-46A, C-46D, C-46F, C-46R, C-46E, C-46/CW20-T, and Super C-46/CW20-T models.
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Federal Register Abstract
Hydraulic Vent System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_57-05-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-05-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: CURTISS-WRIGHT Model C-46 Series Aircraft Subject: Hydraulic Vent System 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: 57-05-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-05-01 SUBJECT HEADING: CURTISS-WRIGHT Model C-46 Series Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 57-05-01 CURTISS-WRIGHT: Applies to all C-46 Series aircraft. Compliance required by August 1, 1957. During emergency extension of the landing gear, hydraulic dump valves are actuated in the landing gear hydraulic system to vent fluid directly overboard in order to prevent trapped fluid from preventing the lowering of the landing gear. On early model aircraft this fluid was vented overboard on the inboard side of the nacelles directly aft of the exhaust stack. This has resulted in fires in areas where no fire detection or protection is provided. In order to prevent this occurrence, item (1), (2), or (3) should be accomplished. (1) The vent line should be rerouted to vent from nacelle tail cone in accordance with Curtiss-Wright Service Bulletin C-46 1226 or Curtiss-Wright Drawing No. 20-575-3206. (2) The vent line should be rerouted to return to the main system as outlined in change A of T.O. 01-25LA-209. (3) The vent line should be rerouted to an approved equivalent of item (1) or (2). Either item (1) or (2) may have been accomplished on later model aircraft at the factory or by the military; however, the aircraft may have been further modified and should be inspected for compliance. FOOTER:
Document Text
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AD Final Rules - DRS_57-05-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 57-05-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: CURTISS-WRIGHT Model C-46 Series Aircraft Subject: Hydraulic Vent System 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: 57-05-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 57-05-01 SUBJECT HEADING: CURTISS-WRIGHT Model C-46 Series Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 57-05-01 CURTISS-WRIGHT: Applies to all C-46 Series aircraft. Compliance required by August 1, 1957. During emergency extension of the landing gear, hydraulic dump valves are actuated in the landing gear hydraulic system to vent fluid directly overboard in order to prevent trapped fluid from preventing the lowering of the landing gear. On early model aircraft this fluid was vented overboard on the inboard side of the nacelles directly aft of the exhaust stack. This has resulted in fires in areas where no fire detection or protection is provided. In order to prevent this occurrence, item (1), (2), or (3) should be accomplished. (1) The vent line should be rerouted to vent from nacelle tail cone in accordance with Curtiss-Wright Service Bulletin C-46 1226 or Curtiss-Wright Drawing No. 20-575-3206. (2) The vent line should be rerouted to return to the main system as outlined in change A of T.O. 01-25LA-209. (3) The vent line should be rerouted to an approved equivalent of item (1) or (2). Either item (1) or (2) may have been accomplished on later model aircraft at the factory or by the military; however, the aircraft may have been further modified and should be inspected for compliance. FOOTER:
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Retrieved: Apr 8, 2026
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