# AD 51-07-01: Throttle Housing

- 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- Superseded by: Nothing supersedes this AD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/7FB998F78DE94D2A86256A56006F9BF3.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/51-07-01

## The airworthiness directive

51-07-01 NAVION: Applies to All Models Having Serial Numbers 1789 Through 2019; 2021 Through 2026; 2028 Through 2142; 2144 Through 2169; 2171 Through 2177; and 2180.

To be accomplished as indicated below.

It has been found that on some of these airplanes throttle housing slippage has occurred at the point where the cable housing is swaged to the ferrule at the instrument panel end. This slippage can result in erratic throttle operation. An inspection of these controls for evidence of housing slippage must be made not later than March 5, 1951. Any control showing evidence of slippage shall be replaced immediately.

It has been found that housing slippage may be caused by the inner shaft in the control head striking the end of the housing when the throttle is moved to the full open position. To prevent such occurrence, a special stop nut must be installed on the throttle shaft in place of the existing jam nut. This special nut, which will prevent the inner shaft from striking the end of the housing, is being furnished by the Ryan Co. and must be installed by July 15, 1951.

(Ryan Field Service Bulletin No. 9, dated September 1, 1950, covers this same 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/51-07-01/models.md
Every aircraft: https://openairdocs.org/ad/51-07-01/aircraft.md

Its text cites no advisory circulars or STCs.

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