# AD 50-38-02: Cooling Fan Rework

- Type: Airworthiness directive
- Status: Current
- Products: Scotts-Bell 47 47B, 47B3, 47D and 47D1
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Registered aircraft: 54 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/341F85ED0CEB255086256A34004E76DC.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/50-38-02

## The airworthiness directive

50-38-02 BELL: (a) Applies to All Models 47B, 47B-S, 47B3, 47B3-S, 47D and 47D-S; (b) Applies to Model 47D1, Serial Numbers 145 Through 164, 174 Through 183.

Compliance required before November 15, 1950.

Service difficulties have been experienced involving fan bearing failure due to improper adjustment of the cooling fan belt. This allows the cooling fan to move forward and jam the cyclic controls. To prevent such failures, fan belt tension should be properly adjusted. In addition, a fan shaft washer should be incorporated to prevent the fan from jamming the cyclic control in case bearing failure does occur.

(Bell Service Bulletin No. 61 dated July 20, 1950, covers this subject for models under (a). Bell Service Bulletin No. 72 dated August 4, 1950, covers this subject for models under (b).)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H-1](https://openairdocs.org/tcds/H-1): Scott's-Bell 47 Inc; names 4 of 9 models: 47B, 47B3, 47D1, 47D

## 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: 54 (54 by airframe model, 0 by engine model)
- Makers: Bell 52, Bell Kitz Kopters 1, Bell-Allied Helicopter 1

Models with the most aircraft:

- [Bell 47D1](https://openairdocs.org/model/bell-47d1): 47 aircraft (airframe model)
- [Bell 47D](https://openairdocs.org/model/bell-47d): 4 aircraft (airframe model)
- [Bell 47B](https://openairdocs.org/model/bell-47b): 1 aircraft (airframe model)
- [Bell Kitz Kopters 47D1](https://openairdocs.org/model/bell-kitz-kopters-47d1): 1 aircraft (airframe model)
- [Bell-Allied Helicopter 47D1](https://openairdocs.org/model/bell-allied-helicopter-47d1): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/50-38-02/models.md
Every aircraft: https://openairdocs.org/ad/50-38-02/aircraft.md

Its text cites no advisory circulars or STCs.

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