# AD 50-10-02: Air Intake Hose

- Type: Airworthiness directive
- Status: Current
- Products: Sierra Hotel Aero Navion (Army L-17A), Navion A (Army L-17B and L-17C) and Navion B
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 746 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/23157D2C705959C186256A56006F9720.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/50-10-02

## The airworthiness directive

50-10-02 NAVION: Applies to all Airplanes, Serial Numbers NAV-4-2 Through NAV-4- 1790.

To be accomplished as indicated below.

The above aircraft employ flexible hose, Ryan Drawing 145-42202, between the exhaust shroud and the carburetor heat valve. This hose has shown a tendency to deteriorate with age and may collapse, resulting in a considerable loss of engine power.

An inspection of these hoses should be made not later than March 20, 1950, and after each 25 hours of aircraft operation until replacement is made with the hose mentioned below. All hoses found to be in poor condition should be replaced immediately by wire reinforced hose. Arrowhead Rubber Co. hose type 8AX (Ryan Drawing No. 145-42202-3) or equivalent is satisfactory.

The installation of the above wire reinforced air intake hose in replacement of the original hose should be accomplished in all aircraft by September 1, 1950.

(Ryan Service Letter No. 67 dated February 7, 1950, also covers this subject.)

## 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 3 of 8 models: Navion B, Navion (Army L-17A), Navion A (Army L-17B and L-17C)

## 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: 746 (746 by airframe model, 0 by engine model)
- Makers: Ryan 353, North American 252, Navion 141

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)
- [Ryan NAVION A](https://openairdocs.org/model/ryan-navion-a): 115 aircraft (airframe model)
- [Navion NAVION A](https://openairdocs.org/model/navion-navion-a): 99 aircraft (airframe model)
- [Ryan NAVION B](https://openairdocs.org/model/ryan-navion-b): 68 aircraft (airframe model)
- [North American NAVION A](https://openairdocs.org/model/north-american-navion-a): 46 aircraft (airframe model)
- [Navion NAVION B](https://openairdocs.org/model/navion-navion-b): 42 aircraft (airframe model)
- [North American NAVION B](https://openairdocs.org/model/north-american-navion-b): 3 aircraft (airframe model)

All 9 models: https://openairdocs.org/ad/50-10-02/models.md
Every aircraft: https://openairdocs.org/ad/50-10-02/aircraft.md

Its text cites no advisory circulars or STCs.

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