# AD 76-12-01: Tail Rotor Hub Bolt - Type: Airworthiness directive - Status: Current - Products: Scotts-Bell 47 47B, 47B3, 47D, 47D1, 47G, 47G-2 and 47H-1 - Effective: July 14, 1976 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-2636 - Registered aircraft: 212 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D40B6ECB397B3B2986256A3400548B82.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/76-12-01 ## The airworthiness directive 76-12-01 BELL: Amendment 39-2636. Applies to Bell Models 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, and 47H-1 helicopters certificated in all categories. Compliance required within 300 hours' time in service after the effective date of this AD unless already accomplished. To prevent possible fatigue failure of tail rotor hub bolt, Part Numbers 47-641-052-3 or - 5, accomplish the following: (a) Remove and disassemble the tail rotor hub and blade assembly. (b) Remove the metal grease seal from each tail rotor blade grip and install the seal, Part Number 47-641-042-3, in each blade grip to clear the head of the hub bolt. (c) Remove the hub assembly bolts, Part Numbers 47-641-052-3 or -5, from the tail rotor hub assembly. Install hub bolts, Part Number 47-641-194-1, in the tail rotor hub as specified in paragraph 6-16.e., Section IV, Models 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, as revised August 15, 1961, or as specified by equivalent FAAapproved procedures. (d) Assemble and track and balance the tail rotor hub and blade assembly as specified in the pertinent Model Maintenance and Overhaul Instruction Manual or as specified in FAA approved equivalent procedures. (e) Compliance with Bell Helicopter Company Service Bulletin No. 47-76-1 dated January 5, 1976, or later approved revision fulfills compliance with this AD. This amendment becomes effective July 14, 1976. ## 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 7 of 9 models: 47H-1, 47B, 47B3, 47D1, 47D, 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: 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/76-12-01/models.md Every aircraft: https://openairdocs.org/ad/76-12-01/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.