# AD 75-07-10: Transfer Gearbox Vertical Bevel Gear Bearing - Type: Airworthiness directive - Status: Current - Products: Honeywell International TFE731-2, TFE731-2A, TFE731-2B, TFE731-2BR, TFE731-2C, TFE731-3, TFE731-3A, TFE731-3AR, TFE731-3B, TFE731-3BR, TFE731-3C, TFE731-3CR and 3 more - Effective: May 1, 1975 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-2189 - Registered aircraft: 1,185 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/41B2EF65CCE288AD86256E0C00739C14.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/75-07-10 ## The airworthiness directive 75-07-10 AIRESEARCH MANUFACTURING COMPANY of ARIZONA: Amendment 39-2144 as amended by Amendment 39-2189. Applies to AiResearch TFE731-2 and -3 series engines. Compliance required as indicated. To detect, prevent and correct wear of the transfer gearbox vertical bevel gear bearing support which can result in failure of the accessory drive and contamination of the engine lubrication system, accomplish the following: (A) Within the next 25 hours time in service after receipt of this Airworthiness Directive, unless previously accomplished, and at intervals not to exceed 50 hours time in service thereafter, inspect the lower shoulder of transfer gearbox vertical bearing support for wear and replacements as required per AiResearch Service Bulletin TFE731-72-3019, dated February 27, 1975, or later FAA-approved revisions. (B) The inspections required by paragraph (A) above, are not required if the engine is equipped with a transfer gearbox assembly, P/N 3070093-3, designated as Series I, Change 2 or Series 3, and may be discontinued on engines equipped with Series I Transfer Gearbox Assemblies when the bearing support, P/N 3070217-1, is replaced with an improved bearing support, P/N 3070217-3, per AiResearch Service Bulletin TFE731-72-3020, dated February 27, 1975, or later FAA-approved revisions. Bearing supports, P/N 3070217-1, which are removed from service shall be rendered unserviceable. (C) Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiating data. (D) Aircraft may be flown to a base for performance of maintenance required by this AD per FAR's 21.197 and 21.199. Amendment 39-2144 became effective April 3, 1975, for all persons except those to whom it was made effective by airmail letters dated February 28, 1975. This amendment 39-2189 becomes effective May 1, 1975. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E6WE](https://openairdocs.org/tcds/E6WE): Honeywell Aerospace US LLC; names 15 of 23 models: TFE731-2A, TFE731-2C, TFE731-3, TFE731-3A, TFE731-3D, TFE731-3R, TFE731-3B, TFE731-2… ## 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: 1,185 (0 by airframe model, 1,185 by engine model) - Makers: Dassault-Breguet 201, Learjet 183, Cessna 155, Raytheon 153, Gates Learjet 134, Dassault 107, Israel Aircraft Industries 98, British Aerospace 50, Raytheon Corporate Jets 29, Gates Lear Jet 28 Models with the most aircraft: - [Garrett TFE731 series](https://openairdocs.org/engine/garrett-tfe731-series): 694 aircraft (engine model) - [Honeywell TFE-731-SER series](https://openairdocs.org/engine/honeywell-tfe-731-ser-series): 291 aircraft (engine model) - [Alliedsign TFE-731-2B](https://openairdocs.org/engine/alliedsign-tfe-731-2b): 69 aircraft (engine model) - [Alliedsign TFE731 series](https://openairdocs.org/engine/alliedsign-tfe731-series): 17 aircraft (engine model) - [Honeywell TFE731-2C](https://openairdocs.org/engine/honeywell-tfe731-2c): 11 aircraft (engine model) - [Honeywell TFE731-2](https://openairdocs.org/engine/honeywell-tfe731-2): 10 aircraft (engine model) - [Honeywell TFE731-3C](https://openairdocs.org/engine/honeywell-tfe731-3c): 10 aircraft (engine model) - [Honeywell TFE731-3D](https://openairdocs.org/engine/honeywell-tfe731-3d): 10 aircraft (engine model) - [Garrett TFE731-3](https://openairdocs.org/engine/garrett-tfe731-3): 9 aircraft (engine model) - [Honeywell TFE-731 series](https://openairdocs.org/engine/honeywell-tfe-731-series): 8 aircraft (engine model) - [Garrett TFE731-3A](https://openairdocs.org/engine/garrett-tfe731-3a): 6 aircraft (engine model) - [Honeywell TFE731-3](https://openairdocs.org/engine/honeywell-tfe731-3): 5 aircraft (engine model) - [Garrett TFE731-3B](https://openairdocs.org/engine/garrett-tfe731-3b): 4 aircraft (engine model) - [Honeywell TFE731-3AR](https://openairdocs.org/engine/honeywell-tfe731-3ar): 4 aircraft (engine model) - [Alliedsign TFE731-2](https://openairdocs.org/engine/alliedsign-tfe731-2): 3 aircraft (engine model) - [Garrett TFE731-2](https://openairdocs.org/engine/garrett-tfe731-2): 3 aircraft (engine model) - [Garrett TFE731-3C](https://openairdocs.org/engine/garrett-tfe731-3c): 3 aircraft (engine model) - [Garrett TFE731-3CR](https://openairdocs.org/engine/garrett-tfe731-3cr): 3 aircraft (engine model) - [Honeywell TFE731-2B](https://openairdocs.org/engine/honeywell-tfe731-2b): 3 aircraft (engine model) - [Honeywell TFE731-3CR](https://openairdocs.org/engine/honeywell-tfe731-3cr): 3 aircraft (engine model) All 33 models: https://openairdocs.org/ad/75-07-10/models.md Every aircraft: https://openairdocs.org/ad/75-07-10/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.