# AD 53-08-01: Horizontal Stabilizer Fitting

- 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- Superseded by: Nothing supersedes this AD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/A6F74B4F8424110686256A56006FB40B.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/53-08-01

## The airworthiness directive

53-08-01 NAVION: Applies to All Models Except Those Incorporating Palo Alto Airport Co. or Symon Engineering Co. Horizontal Stabilizer Modifications.

Compliance required by June 15, 1953, or next 100-hour inspection, whichever is first.

Inspect both 145-21404-1 and -2 front fittings on the horizontal stabilizer for proper rivet edge distance. If the entire outboard edge of the steel fitting extends past the outboard edge of the butt rib, no further action is required. On the other hand, if the edge of the fitting disappears behind the rib, it will be necessary to ascertain that at least 1/16 inch of material (steel fitting) extends beyond the edge of all rivet holes. Whenever the edge distance is found to be less than 1/16 inch, a new fitting should be installed with proper edge distance.

(A method of conducting the above inspection is described in Ryan Field Service Bulletin No. 19, dated February 16, 1953, which 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/53-08-01/models.md
Every aircraft: https://openairdocs.org/ad/53-08-01/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.