# AD 47-31-02: Carburetor Vapor Return Line

- Type: Airworthiness directive
- Status: Current
- Products: Sierra Hotel Aero Navion (Army L-17A)
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 373 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1F1CA6B09035274B86256A56006EE0BB.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/47-31-02

## The airworthiness directive

47-31-02 NAVION: (Was Mandatory Note 11 of AD-782-3.) Applies to Serial Numbers NAV-4-2 Through NAV-4-850.

To be accomplished not later than November 1, 1947.

Remove carburetor vapor return line hose P/N 75696 and install fire-resistant hose P/N 76701. This change is necessary to prevent premature failure of the vapor return line in the event of an engine compartment fire.

(NAA Field Service Bulletin No. 23 dated April 11, 1947, covers this rework.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-782](https://openairdocs.org/tcds/A-782): Sierra Hotel Aero Inc.; names 1 of 8 models: Navion (Army L-17A)

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 373 (373 by airframe model, 0 by engine model)
- Makers: North American 203, Ryan 170

Models with the most aircraft:

- [North American NAVION](https://openairdocs.org/model/north-american-navion): 203 aircraft (airframe model)
- [Ryan NAVION](https://openairdocs.org/model/ryan-navion): 170 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/47-31-02/models.md
Every aircraft: https://openairdocs.org/ad/47-31-02/aircraft.md

Its text cites no advisory circulars or STCs.

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