# AD 56-05-01: Tail Rotor Drive Shafts

- Type: Airworthiness directive
- Status: Current
- Products: Scotts-Bell 47 47, 47B, 47B3, 47D, 47D1, 47E, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B and 12 more
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Registered aircraft: 490 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B9FD0938D6B32C6086256A34004F4313.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/56-05-01

## The airworthiness directive

56-05-01 BELL: Applies to Model 47 Helicopters: Model 47D1 Serial Number 477 and Subsequent, Model 47G Serial Numbers 667 Through 692, 694 Through 1511, Model 47G2 Serial Numbers 1342 Through 1418, Model 47H1 Serial Numbers 1347, 1349 Through 1356, 1358, and 1360, All Model 47 Modified to Include 47-644-172-3 Tail Rotor Extension Drive Shaft and All 47-644-172-3 Shafts in Stock.

Compliance required by March 1, 1956.

As a result of manufacturing error some Bell Model 47 tail rotor extension drive shafts P/N 47-644-172-3 were bored too deep resulting in a weakened wall section. Bell has issued Service Bulletin No. 106 requiring an immediate mandatory inspection by X-ray or by method described in the Service Bulletin.

This supersedes telegraph AD of February 3, 1956.

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 2H3](https://openairdocs.org/tcds/2H3): Scott's-Bell 47 Inc; names 11 of 11 models: 47G-2A, 47G-3B, 47G-3, 47G-4A, 47G-5A, 47G-5, 47G-3B-2A, 47G-3B-2…
- [TCDS H-1](https://openairdocs.org/tcds/H-1): Scott's-Bell 47 Inc; names 9 of 9 models: 47H-1, 47B, 47B3, 47D1, 47D, 47G-2, 47G, 47…
- [TCDS 2H1](https://openairdocs.org/tcds/2H1): Scott's-Bell 47 Inc; names 4 of 4 models: 47K, 47J-2, 47J-2A, 47J

## 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: 490 (490 by airframe model, 0 by engine model)
- Makers: Bell 476, Bell-K-Copter 3, Bell Kitz Kopters 1, Bell-Allied Helicopter 1, Bell-Carson 1, Bell-Huddleston And Wilson 1, Bell-Intermountain 1, Bell-Olympic Helicopters 1, Bell-Shippey 1, Bell-Tellijohn 1

Models with the most aircraft:

- [Bell 47G-2](https://openairdocs.org/model/bell-47g-2): 87 aircraft (airframe model)
- [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1): 86 aircraft (airframe model)
- [Bell 47G](https://openairdocs.org/model/bell-47g): 55 aircraft (airframe model)
- [Bell 47D1](https://openairdocs.org/model/bell-47d1): 47 aircraft (airframe model)
- [Bell 47G-5](https://openairdocs.org/model/bell-47g-5): 40 aircraft (airframe model)
- [Bell 47G-3B-2](https://openairdocs.org/model/bell-47g-3b-2): 26 aircraft (airframe model)
- [Bell 47G-4A](https://openairdocs.org/model/bell-47g-4a): 20 aircraft (airframe model)
- [Bell 47G-2A](https://openairdocs.org/model/bell-47g-2a): 19 aircraft (airframe model)
- [Bell 47G-5A](https://openairdocs.org/model/bell-47g-5a): 19 aircraft (airframe model)
- [Bell 47G-3B](https://openairdocs.org/model/bell-47g-3b): 15 aircraft (airframe model)
- [Bell 47G-2A-1](https://openairdocs.org/model/bell-47g-2a-1): 13 aircraft (airframe model)
- [Bell 47G-4](https://openairdocs.org/model/bell-47g-4): 13 aircraft (airframe model)
- [Bell 47G3B2A](https://openairdocs.org/model/bell-47g3b2a): 7 aircraft (airframe model)
- [Bell 47H-1](https://openairdocs.org/model/bell-47h-1): 6 aircraft (airframe model)
- [Bell 47J](https://openairdocs.org/model/bell-47j): 6 aircraft (airframe model)
- [Bell 47J-2](https://openairdocs.org/model/bell-47j-2): 6 aircraft (airframe model)
- [Bell 47J-2A](https://openairdocs.org/model/bell-47j-2a): 5 aircraft (airframe model)
- [Bell 47D](https://openairdocs.org/model/bell-47d): 4 aircraft (airframe model)
- [Bell-K-Copter 47G](https://openairdocs.org/model/bell-k-copter-47g): 2 aircraft (airframe model)
- [Bell 47B](https://openairdocs.org/model/bell-47b): 1 aircraft (airframe model)

All 35 models: https://openairdocs.org/ad/56-05-01/models.md
Every aircraft: https://openairdocs.org/ad/56-05-01/aircraft.md

Its text cites no advisory circulars or STCs.

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