# AD 75-18-06: Tail Rotor Pitch Control - Type: Airworthiness directive - Status: Current - Products: Scotts-Bell 47 47B, 47B3, 47D, 47D1, 47E, 47G, 47G-2 and 47H-1 - Effective: September 19, 1975 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-2345 - Registered aircraft: 212 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1109E77EDF711C5086256A3400542BBA.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/75-18-06 ## The airworthiness directive 75-18-06 BELL: Amendment 39-2345. Applies to Bell Models 47B, 47B-3, 47D, 47D-1, 47E, 47G, 47G-2, and 47H-1 helicopters certificated in all categories that are equipped with a single-row ball bearing, P/N 47-641-146-1 (MRC R4AF4), in the tail rotor pitch control crosshead. Compliance required within 10 hours' time in service for bearings with more than 40 hours' time in service on the effective date of this AD and prior to attaining 50 hours' time in service for bearings with less than 40 hours' time in service on the effective date of this AD. To prevent possible failure of the tail rotor pitch control ball bearing due to inadequate lubrication, accomplish the following one-time inspection. a. Disassemble the tail rotor pitch control crosshead assembly in accordance with Sections VI and VII, Models 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, revised August 15, 1961, or in accordance with equivalent FAA approved procedures to expose the pitchchange bearing. b. Inspect the bearing, P/N 47-641-146-1 (MRC P/N R4AF4) for grease dust shields. c. Remove any pitch change bearings with two grease dust shields installed before further flight. d. Install bearings P/N 47-641-146-1 (MRC P/N R4AF4) with only one grease dust shield installed and assemble and rig the tail rotor controls, in accordance with Sections VI and VII, Models 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, revised August 15, 1961, or in accordance with equivalent FAA approved procedures. e. This AD does not apply to the obsolete design, single-row ball bearings having a single grease dust shield, Norma Hoffman P/N S1RP and New Departure P/N 7R4AX1C. This AD does not apply to the duplex pitch change bearings, P/N 47-641-131-1. This amendment becomes effective September 19, 1975. ## 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 8 of 9 models: 47H-1, 47B, 47B3, 47D1, 47D, 47G-2, 47G, 47E ## 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: 212 (212 by airframe model, 0 by engine model) - Makers: Bell 200, Bell-K-Copter 3, Bell Kitz Kopters 1, Bell-Allied Helicopter 1, Bell-Carson 1, Bell-Olympic Helicopters 1, Bell-Shippey 1, Bell-Tellijohn 1, Bell-Transworld Helicopter Cor 1, Bell-Yehnert 1 Models with the most aircraft: - [Bell 47G-2](https://openairdocs.org/model/bell-47g-2): 87 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 47H-1](https://openairdocs.org/model/bell-47h-1): 6 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) - [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) - [Bell-Shippey BELL 47G](https://openairdocs.org/model/bell-shippey-bell-47g): 1 aircraft (airframe model) - [Bell-Carson 47G](https://openairdocs.org/model/bell-carson-47g): 1 aircraft (airframe model) - [Bell-Tellijohn 47G-2](https://openairdocs.org/model/bell-tellijohn-47g-2): 1 aircraft (airframe model) - [Bell-K-Copter 47G-2](https://openairdocs.org/model/bell-k-copter-47g-2): 1 aircraft (airframe model) - [Bell-Transworld Helicopter Cor 47G-2](https://openairdocs.org/model/bell-transworld-helicopter-cor-47g-2): 1 aircraft (airframe model) - [Bell-Olympic Helicopters 47G2](https://openairdocs.org/model/bell-olympic-helicopters-47g2): 1 aircraft (airframe model) - [Bell-Yehnert 47G-2](https://openairdocs.org/model/bell-yehnert-47g-2): 1 aircraft (airframe model) - [Continental Copters 47G](https://openairdocs.org/model/continental-copters-47g): 1 aircraft (airframe model) All 17 models: https://openairdocs.org/ad/75-18-06/models.md Every aircraft: https://openairdocs.org/ad/75-18-06/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.