# AD 53-03-01: Hartzell Propeller Vibration

- Type: Airworthiness directive
- Status: Current
- Products: Sierra Hotel Aero Navion B
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 113 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/249B4B81FB0A1B3386256A56006FAFD2.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/53-03-01

## The airworthiness directive

53-03-01 NAVION: Applies to All Model B Aircraft Equipped With Hartzell HC-12 X20-8C/9333C-0 Propellers.

Compliance required not later than March 15, 1953.

Vibration tests conducted subsequent to the initial tests of the Hartzell HC-12 X20- 8C/9333C-0 propeller installed on the Lycoming GO-435 engine revealed vibration characteristics of a hazardous nature. Therefore, to prevent possible blade cracks and/or failures, the existing r.p.m. restriction placard should be revised as follows:

"Avoid continuous ground operation between 1675 and 2150 engine r.p.m."

## 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 B

## 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: 113 (113 by airframe model, 0 by engine model)
- Makers: Ryan 68, Navion 42, North American 3

Models with the most aircraft:

- [Ryan NAVION B](https://openairdocs.org/model/ryan-navion-b): 68 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 3 models: https://openairdocs.org/ad/53-03-01/models.md
Every aircraft: https://openairdocs.org/ad/53-03-01/aircraft.md

Its text cites no advisory circulars or STCs.

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