# AD 56-03-03: Wing Rear Spar Fitting Inspection

- 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- Superseded by: Nothing supersedes this AD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/976B5551808B7B4B86256A56006FC36D.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/56-03-03

## The airworthiness directive

56-03-03 NAVION: Applies to All Models.

Compliance required as indicated.

Cracks starting at the wing centerline attaching bolt hole in the wing rear spar junction fittings (P/N 145-14070) at wing Station O have been found on a number of Navion aircraft.

To correct this, it will be necessary to inspect all Navions for this condition as soon as practicable but not later than May 1, 1956. Access to these fitting may be gained through the main wheel wells.

If no cracks are found, 3/16-inch thick 1010 steel (or equivalent) end plates, properly radiused for a snug fit, should be installed in each fitting prior to the next 50 hours of flight time.

If cracks are found, they should be stop-drilled with a No. 60 (0.040 drill and the end plates as described above should be installed prior to the next flight.

No further inspections will be necessary upon installation of these end plates.

(Ryan Navion Service Bulletin No. 23 dated December 5, 1955, 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/56-03-03/models.md
Every aircraft: https://openairdocs.org/ad/56-03-03/aircraft.md

Its text cites no advisory circulars or STCs.

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