AD 46-23-06
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Noorduyn Aviation Ltd. | Army UC-64 | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes |
| aircraft | Noorduyn Aviation Ltd. | Army UC-64A | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes |
| aircraft | Noorduyn Aviation Ltd. | Army UC-64B | Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes |
Unsafe Condition
The surface combustion fuel burning heater may allow flames or hot gases to contact the belly fuel tank, leading to fuel tank ignition or structural failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Disconnect and plug the fuel line as near the engine as practicable, or install a fire-resistant bulkhead between the heater and belly fuel tank, a pilot-accessible fuel shutoff valve in the fuel line, and shrouds on the heater exhaust and drain lines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
next periodic inspection
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Noorduyn Models Army UC-64, -64A, and -64B airplanes equipped with surface combustion fuel-burning cabin heaters.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Surface Combustion Fuel Burning Heater
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_46-23-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-23-06 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes Subject: Surface Combustion Fuel Burning Heater Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Noorduyn Aviation Ltd. Model: Army UC-64 | Army UC-64A | Army UC-64B Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 46-23-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-23-06 SUBJECT HEADING: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-23-06 NOORDUYN: (Was Mandatory Note 2 of AD-2-578-1.) Applies Only to Army UC-64, -64A, and -64B Airplanes Equipped With Fuel-Burning Cabin Heaters. Required at next periodic inspection. The surface combustion fuel burning heater must be made inoperative by disconnecting and plugging the fuel line as near the engine as practicable unless the following modifications are accomplished: (a) At fire resistant bulkhead must be installed between the heater and the belly fuel tank. A firewall having the fire-resistant qualities specified in CAR 3.624 will be acceptable. (b) A fuel shutoff valve, controllable from the pilots' compartment must be installed in the fuel line between the engine and the heater. (c) Shrouds must be installed on the heater exhaust and drain lines to isolate the lines from the airframe. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_46-23-06.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 46-23-06 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes Subject: Surface Combustion Fuel Burning Heater Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Noorduyn Aviation Ltd. Model: Army UC-64 | Army UC-64A | Army UC-64B Product Type: Aircraft Product Subtype: Small 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: 46-23-06 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 46-23-06 SUBJECT HEADING: Airworthiness Directives; Noorduyn Models Army UC-64, -64A, and -64B Airplanes ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 46-23-06 NOORDUYN: (Was Mandatory Note 2 of AD-2-578-1.) Applies Only to Army UC-64, -64A, and -64B Airplanes Equipped With Fuel-Burning Cabin Heaters. Required at next periodic inspection. The surface combustion fuel burning heater must be made inoperative by disconnecting and plugging the fuel line as near the engine as practicable unless the following modifications are accomplished: (a) At fire resistant bulkhead must be installed between the heater and the belly fuel tank. A firewall having the fire-resistant qualities specified in CAR 3.624 will be acceptable. (b) A fuel shutoff valve, controllable from the pilots' compartment must be installed in the fuel line between the engine and the heater. (c) Shrouds must be installed on the heater exhaust and drain lines to isolate the lines from the airframe. 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.