# AD 47-31-01: Nose Gear Hydraulic Actuating Cylinder Lines

- 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- Superseded by: Nothing supersedes this AD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/44A93602884F096E86256A56006ED725.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/47-31-01

## The airworthiness directive

47-31-01 NAVION: (Was Mandatory Note 10 of AD-782-3.) Applies to All Serials Up to and Including Number NAV-4-947.

To be accomplished not later than October 1, 1947.

To reduce the possibility of nose gear hydraulic actuating cylinder line failures due to inflexibility, the cylinders must be removed and reinstalled with the lines therefrom leading aft. Each of the present lines must be replaced with a longer line incorporating a "U" bend.

(North American Field Service Bulletin No. 28 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 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/47-31-01/models.md
Every aircraft: https://openairdocs.org/ad/47-31-01/aircraft.md

Its text cites no advisory circulars or STCs.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.