# AD 47-11-02: Hartzell Propeller Blade Rework

- 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- Superseded by: Nothing supersedes this AD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/226F28876B3625DE86256A56006E08C3.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/47-11-02

## The airworthiness directive

47-11-02 NAVION: (Was Mandatory note 2 of AD-782-3.) Applies to All Models Equipped With Hartzell HC12x20-1 Propeller Hubs and 8628 Blades.

To be accomplished not later than May 1, 1947.

Vibration tests of the Hartzell HC12x20-1 propeller with these airplanes indicate that the propeller diameter should be reduced from 86 inches to 84 inches. This is accomplished by cutting 1 inch from the tip of each 8628 blade, and making the shortened blade 18428R. This blade rework must be performed either by the Hartzell factory or by a certified propeller repair agency.

(Par. B of North American Field Service Bulletin No. 20 dated January 28, 1947, covers this rework.)

Upon compliance with this AD, the presently required placard against engine operation between 1,950 and 2,150 r.p.m. and over 2,250 r.p.m. may be removed.

## 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/47-11-02/models.md
Every aircraft: https://openairdocs.org/ad/47-11-02/aircraft.md

Its text cites no advisory circulars or STCs.

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