# AD 81-24-08: Turbine Interstage Transition Ducts - Type: Airworthiness directive - Status: Current - Products: Honeywell International TFE731-2, TFE731-3, TFE731-3A, TFE731-3B and TFE731-3R - Effective: January 6, 1982 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-4248 - Registered aircraft: 1,055 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/44D1193B60EF52338625683C006034FF.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/81-24-08 ## The airworthiness directive 81-24-08 GARRETT TURBINE ENGINE COMPANY (formerly the AiResearch Manufacturing Company of Arizona): Amendment 39-4248. Applies to all Model TFE 731-2, -3, -3R, -3A and -3B turbofan engines installed in aircraft certified in all categories equipped with turbine interstage transition ducts, Part No. 3071486-3, -4, -5, -6, or 3072318-1, (hereafter referred to as duct(s)). Compliance required as indicated, unless already accomplished. To prevent separation of the engine rear mount from the duct, accomplish the following: (a) Prior to the accumulation of 350 hours additional time in service from the effective date of this AD, determine from aircraft records or physical inspection whether or not the installed engine model number and serial number is included in the list of engines identified in paragraph 2.C. (Table 1) of Garrett Service Bulletin TFE 731-72-3159 dated April 23, 1981, hereafter referred to as Bulletin -3159. Comply with paragraph (b) or (c) of this AD, asapplicable. The engines listed had acceptable ducts installed during manufacture. (b) For the TFE 731 engines listed in paragraph 2.C. of Bulletin -3159, for which it can be ascertained that the duct has not been replaced since manufacture, prior to the accumulation of 1050 hours additional time in service from accomplishment of paragraph (a), determine the part number and serial number of the installed duct by inspection of the duct identification marking. (1) Determination that the installed duct, by specific part number and serial number, is one of the listed ducts in paragraph 2.D. of Bulletin -3159, constitutes terminating action for this AD. (2) All other part numbers 3071486-3, -4, -5, -6 and 3072318-1 ducts require accomplishment of paragraph (c)(2) of this AD prior to return to service. (c) Prior to return to service after accomplishment of paragraph (a) and with a determination that the installed TFE 731 engine is not one of those listed in paragraph 2.C. of Bulletin -3159, or is listed in paragraph 2.C. of Bulletin -3159 but the duct has been replaced or has an unknown history, determine the installed duct part number and serial number from aircraft records or inspection of the duct identification marking. (1) Determination that the installed duct, by specific part number and serial number, is one on the list of serviceable ducts in paragraph 2.D. of Bulletin -3159 constitutes terminating action for this AD. NOTE: The ducts listed in paragraph 2.D. of Bulletin -3159 have been radiographic (x-ray) inspected during the manufacturing process and may be continued in service with no further action required by this AD. (2) All other Part Numbers 3071486-3, -4, -5, -6, and 3072318-1 ducts must be replaced with a serviceable duct, or x-ray inspected in accordance with paragraph (d), or proof load inspected in accordance with paragraph (e), or modified by installing an aft mount auxiliary bracket in accordance with paragraph(f) of this AD, before the engine may be returned to service. (d) Radiographic (x-ray) inspect the electron beam weld attachment of all three engine rear mount clevises on each duct in accordance with instructions provided in Paragraph 2.D. of Bulletin -3159. (1) If the x-ray inspection of all three engine mount clevises is acceptable, reidentify the duct with identifier code of the x-ray facility and new part number as follows: Part Number 3072318-1 is reidentified as Part Number 3072318-3. Part Number 3071486-3 is reidentified as Part Number 3071486-7. Part Number 3071486-4 is reidentified as Part Number 3071486-8. Part Number 3071486-5 is reidentified as Part Number 3071486-9. Part Number 3071486-6 is reidentified as Part Number 3071486-10. (2) If the x-ray inspection of the three engine mount clevises reveals an unsatisfactory weld penetration at a position which is not used to mount the engine to the aircraft, the mount is to be destroyed by cutting through the unsatisfactory clevis mounting bolt hole and the duct reidentified. The bolt hole cut through and duct reidentification must be in accordance with Paragraph 2.F. of Bulletin -3159 as follows: Part Number 3072318-1 is reidentified as Part Number 3076070-1. Part Number 3071486-3 is reidentified as Part Number 3071486-11. Part Number 3071486-4 is reidentified as Part Number 3071486-12. Part Number 3071486-5 is reidentified as Part Number 3071486-13. Part Number 3071486-6 is reidentified as Part Number 3071486-14. (3) If the x-ray inspection of the three engine mount clevises reveals an unsatisfactory weld penetration at a position which is used to mount the engine to the aircraft, the duct must either be rejected or modified by incorporating an aft mount auxiliary bracket in accordance with paragraph (f) of this AD. All unsatisfactory engine mount clevises not used to mount the engine are to have those unsatisfactory clevis mounting bolt holes cut through inaccordance with Paragraph 2.F.(1) of Bulletin -3159. Reidentify ducts in accordance with paragraph (f) of this AD. (e) Inspect the electron beam weld attachment of all three engine rear mount clevises on the duct by performing a proof load inspection in accordance with instructions provided in Paragraph 2.E. of Bulletin -3159. (1) If the proof load inspection of all three engine mount clevises is acceptable, reidentify the duct by electrochemically etching "PL1" (0.0004 inch maximum depth) as a suffix to the existing duct part number. The duct may then be returned to service for a period not to exceed 1050 hours additional time in service, at which time either reinspect the duct by performing the proof load inspection again, or perform a radiographic (x- ray) inspection in accordance with Paragraph (d) of this AD, or modify the duct using the aft mount auxiliary bracket in accordance with Paragraph (f) of this AD, or replace with a serviceable duct. (2) If a second proof load inspection of all three engine mount clevises is acceptable, reidentify the duct by electrochemically etching "PL2" (0.0004 inch maximum depth) as a suffix to the existing duct part number. The duct may be returned to service for a second and final period not to exceed 1050 hours additional time in service. At or before the completion of this additional period of service, the duct must be either inspected by radiographic (x-ray) inspection in accordance with Paragraph (d) of this AD, or modified using the aft mount auxiliary bracket in accordance with Paragraph (f) of this AD, or replaced with a serviceable duct. "PL1" adjacent to the unchanged duct part number indicates the first successful accomplishment of the proof load inspection of all three engine mount clevises. "PL2" adjacent to "PL1" following the unchanged duct part number indicates the second successful accomplishment of the proof load inspection of all three engine mount clevises. (3) If the proof load inspection of the three engine mount clevises reveals an unsatisfactory weld penetration at a position which is not used to mount the engine to the aircraft, provided the engine mount clevis which is to be used for aircraft installation is found acceptable, the ducts are to be modified by cutting through the unacceptable mounting bolt hole of the engine mount clevis in accordance with paragraph 2.F.(1) of Bulletin - 3159. Ducts are to be reidentified by electrochemically etching a new part number thereon, (0.0004 inch maximum depth) as follows: Part Number 3072318-1 is reidentified as Part Number 3076070-1 PL1 Part Number 3071486-3 is reidentified as Part Number 3071486-11 PL1 Part Number 3071486-4 is reidentified as Part Number 3071486-12 PL1 Part Number 3071486-5 is reidentified as Part Number 3071486-13 PL1 Part Number 3071486-6 is reidentified as Part Number 3071486-14 PL1 The duct may be returned to service for a period not to exceed 1050 hours additional timein service, at which time the duct must be replaced with a serviceable duct, reinspected by a second proof load inspection (PL2), inspected by radiographic (x-ray) inspection in accordance with paragraph (d) of this AD, or modified using the auxiliary aft mount bracket, in accordance with paragraph (f) of this AD. (i) Ducts with a second satisfactory proof load inspection of the engine mount clevis used for aircraft installation are to be reidentified by electrochemically etching "PL2" as suffix to the previously reidentified duct part number, i.e., 3071486-14PL1 PL2. At or before a period not to exceed 1050 hours additional time in service after the second proof load inspection of the engine mount clevis the duct must be replaced with a serviceable duct, radiographic (x-ray) inspected in accordance with paragraph (d) of this AD, or modified using the aft mount auxiliary bracket, as allowed in paragraph (f) of this AD. (ii) Ducts which fail the second proof load inspection must comply with paragraph (d) or (f) of this AD or be removed from service. (4) If the proof load inspection of the three engine mount clevises reveals an unsatisfactory weld penetration at a position which is used to mount the engine to the aircraft on which it is to be installed, the duct may be modified by incorporating an aft mount auxiliary bracket in accordance with paragraph 2.B., omitting paragraph 2.B.(10), of Garrett Service Bulletin TFE 731-72-3170, dated April 23, 1981. Reidentify as designated in following paragraph. Engine mount clevises found to have unsatisfactory weld penetration at other positions not used to mount the engine are to have those unsatisfactory clevis mounting bolt holes cut through in accordance with paragraph 2.F.(1) of Bulletin -3159. Ducts modified by incorporating an aft mount auxiliary bracket after failing proof load inspection are to be reidentified by electrochemically etching (to a maximum depth of 0.0004 inch) the duct with the following part numbers: Old Part No. Auxiliary Bracket Location Looking forward along engine axis from the rear New Part No. 3071486-3/-4/-5/-6 Left 3073362-1 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Top 3073362-2 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Right 3073362-3 PL1 PL2 as applicable 3072318-1 Left 3073362-4 PL1 PL2 as applicable 3072318-1 Top 3073362-5 PL1 PL2 as applicable 3072318-1 Right 3073362-6 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Left and Top 3073362-7 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Top and Right 3073362-8 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Left and Right 3073362-9 PL1 PL2 as applicable 3071486-3/-4/-5/-6 Left, Top and Right 3073362-10 PL1 PL2 as applicable 3072318-1 Left and Top 3073362-11 PL1 PL2 as applicable 3072318-1 Top and Right 3073362-12 PL1 PL2 as applicable 3072318-1 Left and Right 3073362-13 PL1 PL2 as applicable 3072318-1 Left, Top and Right 3073362-14 PL1 PL2 as applicable The aft mount auxiliary bracket requires a longer rear engine mount bolt which is a new aircraft part. Therefore, each type aircraft will require an FAA approved service bulletin to complete the installation. If an FAA approved aircraft service bulletin is not available for the particular installation required, the duct must be returned to the engine manufacturer. (f) Modify the duct by installing an aft mount auxiliary bracket at the mount clevis position which is to be used to mount the engine to the aircraft in accordance with paragraph 2.B. of Garrett Service Bulletin TFE 731-72-3170 dated April 23, 1981. The aft mount auxiliary bracket requires a longer rear engine mount bolt which is a new aircraft part. Therefore, each type aircraft will require an FAA approved service bulletin to complete the installation. If an approved aircraft service bulletin is not available for the particular installation required, the duct must be returned to the engine manufacturer. Ducts which are modified by incorporating this aft mount auxiliary bracket may not have the bracket removed and be returned to service unless the radiographic (x-ray) inspection of all three engine mount clevises in accordance with paragraph (d)(1) of this AD is performed and the weld penetration of all three clevises is found to be satisfactory. If the x-ray inspection of all three engine mount clevises is acceptable, reidentify the duct with identifier code of the x-ray facility and new part number as provided for in paragraph 2.D.(4) of Bulletin -3159. NOTE: Ducts with an engine mount clevis found to have improper weld penetration or which have had any clevis cut through in accordance with paragraph 2.F. of Bulletin -3159 may be returned to the engine manufacturer. The duct may be returned to service when it is determined to be serviceable. Special flight permits may be issued in accordance with FAR 21.197 and21.199 to operate airplanes to a base for the accomplishment of inspections or modifications required by this AD. Alternative inspections, modifications, or other actions which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA Western-Pacific Region. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Garrett Turbine Engine Company, P.O. Box 5217, Phoenix, Arizona 85010. These documents may also be examined at FAA Western-Pacific Region Office, Rules Docket in Room 6W14, 15000 Aviation Boulevard, Hawthorne, California 90261 and at FAA Headquarters, Rules Docket in Room 916, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historicalfile on this AD, which includes the incorporated material in full, is maintained by the FAA at its Headquarters in Washington, D.C. and at FAA Western-Pacific Region Office. This amendment becomes effective January 6, 1982. ## 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 5 of 23 models: TFE731-3, TFE731-3A, 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: 1,055 (0 by airframe model, 1,055 by engine model) - Makers: Dassault-Breguet 181, Raytheon 153, Cessna 143, Learjet 140, Gates Learjet 123, Dassault 91, Israel Aircraft Industries 85, British Aerospace 49, Raytheon Corporate Jets 27, Gates Lear Jet 24 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 TFE731 series](https://openairdocs.org/engine/alliedsign-tfe731-series): 17 aircraft (engine model) - [Honeywell TFE731-2](https://openairdocs.org/engine/honeywell-tfe731-2): 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) - [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) - [Honeywell TFE731-3R](https://openairdocs.org/engine/honeywell-tfe731-3r): 2 aircraft (engine model) - [Alliedsign TFE731-3R](https://openairdocs.org/engine/alliedsign-tfe731-3r): 1 aircraft (engine model) - [Garrett TFE731-3R](https://openairdocs.org/engine/garrett-tfe731-3r): 1 aircraft (engine model) - [Honeywell TFE731-3B](https://openairdocs.org/engine/honeywell-tfe731-3b): 1 aircraft (engine model) All 15 models: https://openairdocs.org/ad/81-24-08/models.md Every aircraft: https://openairdocs.org/ad/81-24-08/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.