# AD 56-25-02: Tail Rotor Pitch Bearings

- 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- Superseded by: Nothing supersedes this AD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/8A88F82CD04A158F86256A34004F957F.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/56-25-02

## The airworthiness directive

56-25-02 BELL: Applies to All Model 47 Series Helicopters Except the Following: Model 47G Serial Numbers 1529, 1530, 1687 and Up; Model 47G2 Serial Numbers 1505, 1506, 1508, 1617 and Up; Model 47H1 Serial Numbers 1369, 1371 and Up; Model 47J.

Compliance required by December 22, 1956.

Excessive tolerance resulting from wear of the tail rotor pitch change rod assembly can result in the loss of the S1RP or 7R4AX1C bearings. To preclude loss of these bearings, the AN 960-416 washer or washers, P/N 47-641-113-1, made to the dimensions 0.562-0.557 inch must be replaced with washers that have an O.D. dimension not greater than 0.552 inch or less than 0.549 inch.

(Bell Mandatory Service Bulletin No. 113 Revision B dated October 23, 1956, covers this same subject.) This supersedes AD 56-20-02.

## 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/56-25-02/models.md
Every aircraft: https://openairdocs.org/ad/56-25-02/aircraft.md

Its text cites no advisory circulars or STCs.

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