# AD 50-12-01: Propeller Blade

- Type: Airworthiness directive
- Status: Current
- Products: Hamilton Standard Propeller Blades, W670-16, W670-6A and W670-6N
- Superseded by: Nothing supersedes this AD
- Product type: Appliance
- Registered aircraft: 1,076 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0B33BDD6535E4B398625696500497720.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/50-12-01

## The airworthiness directive

50-12-01 HAMILTON STANDARD: Applies to All Aircraft Equipped With Continental Engines, Models W-670-6A (R-670-3, -5), W-670-6N (R-670-4), W-670-16 (R-670-8, -11, - 11A) and Hamilton Standard Ground Adjustable Propellers Having Blades, Model 11C1 (Navy 4350, 4350F, 4350F1).

Compliance required not later than April 15, 1950.

To minimize the possibility of propeller blade shank fatigue failures as a result of noncompliance with a mandatory engine operation restriction, the following precautionary measures should be taken:

  (1) Check the marking on the engine tachometer and correctly mark it, if necessary, with a red arc which covers the entire r.p.m. range above the higher side of the 1,900 r.p.m. graduation.

  (2) Install placard in aircraft to read: "Avoid all engine operation above 1,900 r.p.m. except during takeoff".

  (3) Check position of the propeller and correctly index, if necessary, in the zero degree position (blades in line with crankthrow).

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E-162](https://openairdocs.org/tcds/E-162): Air Repair Inc.; names 3 of 7 models: W670-6A, W670-16, W670-6N

## 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: 1,076 (0 by airframe model, 1,076 by engine model)
- Makers: Boeing 639, Waco 212, Cessna 64, Fairchild 26, Curtiss Wright 22, Jones Peter M 13, Grumman 11, Travel Air 11, Timm 7, Stinson 5

Models with the most aircraft:

- [Continental W670 series](https://openairdocs.org/engine/continental-w670-series): 987 aircraft (engine model)
- [Continental W670-6N](https://openairdocs.org/engine/continental-w670-6n): 52 aircraft (engine model)
- [Continental W670-6A](https://openairdocs.org/engine/continental-w670-6a): 37 aircraft (engine model)

All 3 models: https://openairdocs.org/ad/50-12-01/models.md
Every aircraft: https://openairdocs.org/ad/50-12-01/aircraft.md

Its text cites no advisory circulars or STCs.

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