# AD 46-23-06: Surface Combustion Fuel Burning Heater

- Type: Airworthiness directive
- Status: Current
- Products: Noorduyn Army UC-64, Army UC-64A and Army UC-64B
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2EAAB2C98D62A38D86256A450067FC68.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/46-23-06

## The airworthiness directive

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.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-2-578](https://openairdocs.org/tcds/A-2-578): Noorduyn Aviation Ltd.; names 3 of 7 models: Army UC-64B, Army UC-64, Army UC-64A

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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