# AD 70-14-01: Tail Rotor Pitch - Type: Airworthiness directive - Status: Current - Products: Scotts-Bell 47 47D1, 47G, 47G-2 and 47H-1 - Effective: August 17, 1970 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-1065 - Registered aircraft: 207 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1ECAF8479C36981386256E01005AC89C.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/70-14-01 ## The airworthiness directive 70-14-01 BELL: Amdt. 39-1022 as amended by Amendment 39-1065. Applies to all Bell Model 47D-1, 47G, 47G-2, and 47H-1 helicopters certificated in all categories and to any other helicopters equipped with duplex pitch change bearings, P/N 47-641-131-1. Compliance required as indicated. To prevent possible failure of tail rotor duplex pitch change bearing and to correct any improper installation of the duplex bearing and delta hinge bolts: (a) Inspect all duplex pitch change bearings within the next 50 hours time in service after the effective date of this AD, unless already accomplished, as follows: (1) Remove tail rotor assembly. (2) Remove and disassemble the tail rotor drive head assembly to expose the duplex bearings and guide sleeve, P/N 47-641-040 or 47-641-130. (3) Inspect the outside surface of the guide sleeve for scoring. (4) Inspect the duplex bearing for roughness. (5) Replace the duplex bearing before further flight as specified in subparagraphs (b)(3) and (4) if the guide sleeve is scored or if the bearing is rough. (6) Install the tail rotor assembly and check rigging and tracking as described in subparagraph (b)(5). (b) Remove and replace duplex pitch change bearings with 450 or more hours time in service on the effective date of this AD within the next 150 hours time in service, as follows: (1) Remove tail rotor assembly, (2) Remove and disassemble the tail rotor drive head assembly, (3) Assemble and install the tail rotor drive head assembly, using a new duplex bearing, P/N 47-641-131-1, in accordance with the procedures specified in Paragraphs 6.63(j) and (k) in the Model 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, as revised August 15, 1961, or in accordance with FAA approved equivalent procedures. (4) Lubricate the bearing and sleeve with grease, MIL-G-25537 or equivalent. (5) Install the tail rotor assembly and check rigging and tracking in accordance with the procedures specified in Paragraphs 6-17(a) through (h) or 6-18(a) through (g) of the appropriate manual or in accordance with FAA approved equivalent procedures. (c) Remove and replace duplex pitch change bearings with less than 450 hours time in service on the effective date of this AD prior to accumulating 600 hours time in service, in accordance with the procedures described in subparagraphs (b)(1) through (5) above. (d) Remove and replace all replacement duplex pitch change bearings prior to accumulating 600 hours time in service. Amendment 39-1022 effective August 10, 1970. This Amendment (39-1065) becomes effective August 17, 1970. ## 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: 47H-1, 47D1, 47G-2, 47G ## 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: 207 (207 by airframe model, 0 by engine model) - Makers: Bell 195, 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-K-Copter 47G](https://openairdocs.org/model/bell-k-copter-47g): 2 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 15 models: https://openairdocs.org/ad/70-14-01/models.md Every aircraft: https://openairdocs.org/ad/70-14-01/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.