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.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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