# AD 47-41-04: Main Rotor Mast Plug

- Type: Airworthiness directive
- Status: Current
- Products: Scotts-Bell 47 47B and 47B3
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Registered aircraft: 1 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A5345EB5E5E7B71286256A34004DE056.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/47-41-04

## The airworthiness directive

47-41-04 BELL: (Was Mandatory Note 16 of AD-1H-2.) Applies to Models 47B and 47B3 Helicopters.

Compliance required not later than next 50-hour transmission teardown inspection after December 1, 1947.

To improve attachment of the inner race bearing on the bottom of the main rotor mast and to prevent possible chipping, the lower mast plug should incorporate a bolted retaining washer.

(Bell Service Bulletin 47C41 dated June 26, 1947, covers the detail installation.)

## 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 2 of 9 models: 47B, 47B3

## 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 (1 by airframe model, 0 by engine model)
- Makers: Bell 1

Models with the most aircraft:

- [Bell 47B](https://openairdocs.org/model/bell-47b): 1 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/47-41-04/models.md
Every aircraft: https://openairdocs.org/ad/47-41-04/aircraft.md

Its text cites no advisory circulars or STCs.

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