# General Electric Service Bulletin 72-A0118: Revision 01 - Rights: © General Electric Company. Filed by the FAA in regulations.gov docket FAA-2024-0774, the docket of AD 2024-06-51. Not covered by OpenAirDocs’ CC0 dedication. - Document: [General Electric Service Bulletin 72-A0118](https://openairdocs.org/service-documents/ge/72-a0118.md) - Title as filed: General Electric Alert Service Bulletin CT7-8 SB 72-A0118 Rev 1 - Pages: 13 - PDF: https://openairdocs.org/files/sha256/86/9c/869c5e0427faebd7ad0566a393901a5b7bd9e1d29773046ad698a91a702a19f1 - Page: https://openairdocs.org/service-documents/ge/72-a0118/file/869c5e0427fa ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection GE Designated: -CONFIDENTIAL- The information contained in this document is GE proprietary information and is disclosed in con¿dence. It is the property of GE and shall not be used, disclosed to others or reproduced without the express written consent of GE, including, but without limitation, it is not to be used in the creation, manufacture, development, or derivation of any repairs, modi ¿cations, spare parts, designs, or con ¿guration changes or to obtain FAA or any other government or regulatory approval to do so. If consent is given for reproduction in whole or in part, this notice and the notice set forth on each page of this document shall appear in any such reproduction in whole or part. This technical data is considered subject to the Export Administration Regulations (EAR) pur- suant to 15 CFR Parts 730-774. Transfer of this data by any means to a Non-U.S. Person, whether in the United States or abroad, without the proper U.S. Government authorization (e.g., License, exemption, NLR, etc.), is strictly prohibited. Copyright (2024) General Electric Company, U.S.A. TRANSMITTAL INFORMATION REVISION 1 TO ALERT SERVICE BULLETIN 72-A0118 Revision 1 is issued to update the affected engine population listed in Appendix A and adds the effectivity to a single CT7-8A7 engine. The original Alert Service Bulletin was issued February 26, 2024. Revision bars in the left margin identify changes. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 1 of 13 ### Page 2 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection 1. PLANNING INFORMATION A. Effectivity CT7-8A, CT7-8A7, CT7-8E, CT7-8F5 This Alert Service Bulletin is applicable to CT7-8A, CT7-8A7, CT7-8E and CT7-8F5 engine models with power turbine (PT) drive shaft assembly part numbers (P/N) 5123T91G01, 5123T91G02, and 5128T51G01 installed with less than 100 hours-time since new (TSN) or 100 hours-time since replacement (TSR) of the PT drive shaft assembly produced or made between 2020 and 2023. The affected engine serial numbers (ESN), PT module serial numbers (S/N), or part S/Ns listed in this Alert Service Bulletin is the best available data. See Appendix A, T able 1 for a list of applicable ESNs. See Appendix A, T able 2 for a list of applicable PT module S/Ns. See Appendix A, T able 3 for a list of applicable part S/Ns. B. Description This Alert Service Bulletin provides instructions to remove the engine C-sump cover and use an Ultrasonic T est (UT) Phase Array probe to inspect the PT drive shaft assembly reference tube magnetic insert end braze joint. C. Compliance Category 1 GE recommends that you do this Alert Service Bulletin before subsequent Àight. Non-passenger operation is allowed for repositioning the aircraft to a maintenance facility if required. Impact A This recommendation is to address a condition that may affect Àight safety. NOTE: This Alert Service Bulletin can be done on wing or in shop. D. Concurrent Requirements None. E. Reason (1) Objective: This Alert Service Bulletin provides an inspection to verify the minimum acceptable braze coverage on the PT drive shaft assembly reference tube magnetic insert. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 2 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 3 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection (2) Condition: Multiple PT drive shaft assemblies were shipped with inadequate braze coverage on the end of the PT shaft reference tube magnetic insert joint. (3) Cause: Inadequate braze coverage within the torque reference tube magnetic insert joint can become compromised leading to improper torque and speed indications. (4) Improvement: Planning has been updated and UT Phase Array probe inspection has been incorporated into the manufacturing process of the torque reference tube assembly. (5) Substantiation: Substantiation is by analysis and ¿eld experience. F. Approval The data contained in this Alert Service Bulletin has been reviewed by the FAA or authorized entity representing the FAA and the repair(s) and modi ¿cation(s) herein comply with the applicable Aviation Regulations and are APPROVED for installation in the model(s) listed in this Alert Service Bulletin. G. Manpower You will need approximately one man-hour to do this Alert Service Bulletin once the area is exposed. H. Weight and Balance Weight and balance are not changed. I. References (Use the latest version of these documents) CT7-8 Turboshaft Engine Service Record FST-2572, Phase Array Ultrasonic Inspection Procedure GEK 105158, CT7-8 Illustrated Parts Catalogue (IPC) GEK 105159, CT7-8 Maintenance Manual (MM) GEK 105175, CT7-8 Shop Manual (SM) J. Publications Affected None. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 3 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 4 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection K. Interchangeability Not applicable. L. Software Accomplishment Summary Not applicable. 2. MATERIAL INFORMATION A. Material - Price and Availability (1) Parts necessary to do this Alert Service Bulletin: Part Number Qty/ Eng Part Name Unit ($) Price Pkg Qty Lead Time Days 4074T58P04 72-50-00-01-060A (1) Packing, Preformed (SIN 91652) Quote (-) Quote J1400P011 72-50-00-01-060B (Alt) Packing, Preformed (SIN 91652) Quote (-) Quote 4074T58P09 72-50-00-01-070A (1) Packing, Preformed (SIN 91650) Quote (-) Quote J1400P159 72-50-00-01-070B (Alt) Packing, Preformed SIN 91650 Quote (-) Quote (2) Other Spare Parts: None. (3) Consumables: Code Number Description C02-007 Assembly Fluid, Ultrachem No. 1 -- Oil, Engine B. Industry Support Information Not applicable. C. Con¿guration Chart Not applicable. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 4 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 5 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection D. Parts Disposition See paragraph 3., A CCOMPLISHMENT INSTRUCTIONS. E. Tooling - Price and Availability Part Number Nomenclature GE-FQAP-803 Ultrasonic Probe T est Kit (Provided by GE Aerospace) 3. ACCOMPLISHMENT INSTRUCTIONS A. General NOTE 1: T o accomplish this inspection there must be access to the engine C-sump heat shield to allow removal of the heat shield and the C-sump cover to insert the Phase Array Probe (approximately 12.5 inches (318 mm)). The inspection also requires power for an ultrasonic instrument (approximately 12 inches x 12 inches x 6 inches (305 mm x 305 mm x 152 mm)) which must be visually observed by the inspector during the test and must be in close proximity to the probe. This may require removal of the engine from the aircraft in some installations. This inspection may also be carried out on an engine stand or in an engine storage container with the lid removed. NOTE 2: Review the engine log book for the installation time of the installed PT drive shaft assembly P/N 5123T91G01, 5123T91G02, or 5128T51G01. If the current operational time on the part since installation is over 100 hours, compliance with this Alert Service Bulletin is satis ¿ed. Go to paragraph 3.B.(3) and record compliance with this Alert Service Bulletin. If the PT drive shaft assembly is less than 100 hours, proceed with the remainder of this Alert Service Bulletin. NOTE 3: This procedure gives instructions to remove the C-sump heat shield (01-020, Figure 1) and C-sump cover (01-040) to inspect the magnetic insert braze joint on the PT drive shaft assembly (01-070B, Figure 2 and Figure 3). (1) Remove the C-sump heat shield (01-020, Figure 1) and C-sump cover (01-040). Refer to CT7-8 MM GEK 105159, 72-50-00, DISASSEMBLY 001, TASK 72-50-00-030-001, paragraph 3.B. NOTE: The UT Phase Array Probe inspection must be performed by a level 2 or 3 NDT ultrasonic inspector who has been trained by GE Aerospace. (2) Following the GE proprietary inspection procedure FST-2572 - Phase Array Ultrasonic Inspection Procedure for the torque reference tube, perform the braze inspection to quantify the percentage of braze. (a) If the percentage of braze is greater than or equal to 42%, the engine may be returned to service. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 5 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 6 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection (b) If the percentage of braze is less than 42%, tag the engine as failed PT shaft UT inspection and return the engine or PT module to an MRO shop for repair or replacement of the PT drive shaft assembly. (3) Once the inspection is completed, re-install the C-sump cover (01-040, Figure 1) and C-sump heat shield (01-020). Refer to CT7-8 MM GEK 105159, 72-50-00, ASSEMBLY 001, TASK 72-50-00-430-001, paragraph 3.C. (4) For installed engines that have passed inspection, perform required checks. Refer to CT7-8 MM GEK 105159, 72-00-00, TESTING 002, TASK 72-00-00-760-002 (Checkout Procedures after Replacement or Reinstallation of Parts), 72-00-00, TESTING 004, TASK 72-00-00-760-004 (Idle Speed Leakage Check), and 72-00-00, TESTING 005, TASK 72-00-00-760-005 (Oil Consumption Check). (5) For spare engines at the operator that have passed inspection, perform the following: (a) Go to paragraph 3.B., C ompliance as the inspection will meet the intent of this Alert Service Bulletin. When the engine is installed in an aircraft, perform the required checks. Refer to CT7-8 MM GEK 105159, 72-00-00, TESTING 004, TASK 72-00-00-760-004 (Idle Speed Leakage Check) and 72-00-00, TESTING 005, TASK 72-00-00-760-005 (Oil Consumption Check). (6) For engines and modules at an MRO facility that have passed inspection, perform the following: (a) T est engines per CT7-8 SM GEK 105175, 72-00-00, TESTING 013, TASK 72-00-00-760-013 (Idle Speed Leakage Check) and 72-00-00, TESTING 011, TASK 72-00-00-760-011 (Oil Consumption Check). (b) T est modules per CT7-8 SM GEK 105175, 72-00-00, TESTING 006, TASK 72-00-00-760-006 (Engine and Individual Module T est Requirements) (Engine Start, Idle Speed Leakage, Transient, and Engine Shutdown Checks). B. Compliance (1) Record information in T able A. (2) Provide copies of T able A and the GE UT inspection report to the GE Field Service Representative and the Customer Representative. (3) Record compliance of this Alert Service Bulletin in the appropriate CT7 Turboshaft Engine Service Record. February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 6 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 7 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection TABLE A - POWER TURBINE DRIVE SHAFT ASSEMBLY INSPECTION RESULTS Engine or PT Module S/N (if applicable) PT Drive Shaft Assembly P/N PT Drive Shaft Assembly S/N PT Shaft Time Since New (Hours) PT Shaft Time Since Repair (Hours) %B r a z e Coverage Date Work Performed by (Print Name): Signature: Date: February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 7 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 8 (OCR) Avio S.p.A GE Aircraft Engines CT7-8 TURBOSHAFT ENGINE ALERT SERVICE BULLETIN ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection POWER LOCKNUT TURBINE MODULE BOLT (01-030) PREFORMED (01-050) PACKING (01-070) C-SUMP C-SUMP PREFORMED COVER HEAT SHIELD PACKING (01-040) (01-020) (01-060) NOTE: ALL IPC REFERENCES ARE FROM 72-50-00 UNLESS SPECIFIED DIFFERENTLY. 6045650-00 C-Sump Heat Shield and C-Sump Cover - Removal and Installation Figure 1 February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 8 GE Designated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 9 (OCR) Avio S.p.A GE Aircraft Engines CT7-8 TURBOSHAFT ENGINE ALERT SERVICE BULLETIN ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection REFERENCE TABS AFT END OF POWER TURBINE SHAFT 6045651-00 C-Sump and Aft End of Power Turbine Shaft Figure 2 February 26, 2024 C17-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 9 GE Designated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 10 (OCR) Avio S.p.A GE Aircraft Engines CT7-8 TURBOSHAFT ENGINE ALERT SERVICE BULLETIN ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection TORQUE SENSOR TUBE (01-120A) REAR INSERT (01-110A) POWER TURBINE SHAFT (01-080B) PREFORMED PIN PACKING (01-060) (01-090A) FRONT INSERT (01-126) LOCKNUT PIN (01-090) (01-040) PIN (01-090A) POWER TURBINE DRIVE SHAFT ASSY (01-070B) NOTE: ALL IPC REFERENCES ARE FROM 72-52-00 UNLESS SPECIFIED DIFFERENTLY. 6045652-00 Power Turbine Drive Shaft Assembly Figure 3 February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 10 GE Designated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 11 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection 4. APPENDIX A TABLE 1 - AFFECTED ENGINE SERIAL NUMBERS CT7-8A CT7-8A7 CT7-8E CT7-8F5 Engine S/N Part S/N Engine S/N Part S/N Engine S/N Part S/N Engine S/N Part S/N 947217 GATJAWT3 530025 GATJ9GMA 087026 Unknown 731051 GATJ9HPT 947225 Unknown 087027 Unknown 731052 GATJACJ0 947231 Unknown 087028 Unknown 731053 GATJAL85 947239 GATJAF0E 087029 Unknown 731054 GATJ9TM4 947240 GATJ9PT0 087031 GATJC09A 731055 GATJAHD9 947293 Unknown 953181 GATJA1PE 731056 GATJAWPE 947321 GATJALJP 953182 GATJA5DC 731057 GATJAWRL 947337 GATJ9GN2 953183 GATJ855R 731058 GATJC76E 947344 Unknown 953184 GATJA49L 731059 GATJC66H 947350 GATJ36L7 953186 GATJAF34 947405 Unknown 953188 GATJAD4T 947429 Unknown 953190 GATJAKMT 947435 GATJ9PRW 947448 GATJ9F0J 947451 Unknown 947455 GATHJR61 947464 GATJ9N6L 947500 Unknown 947505 Unknown 947570 GATJ37CA 947577 Unknown 947598 Unknown 947611 GATJAD06 947624 Unknown 947625 GATJCATH 947639 Unknown 947640 Unknown February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 11 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 12 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection CT7-8A CT7-8A7 CT7-8E CT7-8F5 Engine S/N Part S/N Engine S/N Part S/N Engine S/N Part S/N Engine S/N Part S/N 947643 Unknown 947679 Unknown 947689 GATJAKF7 947785 Unknown 947796 GATJAKD4 947815 GATJ9JA2 947829 GATJAKMN 947850 GATJALNF 947879 GATJ9EP7 947909 Unknown 947946 GATJ97TP TABLE 2 - AFFECTED POWER TURBINE MODULE SERIAL NUMBERS PT Module S/N Part S/N PT Module S/N Part S/N GE-L947225 GATJC66J GE-L947577 Unknown GE-L947233 GATHMWKJ GE-L947639 Unknown GE-L947338 GATJ0R5G GE-L947640 Unknown GE-L947566 Unknown February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 12 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media ### Page 13 ENGINE - Power Turbine Module (72-50-00) - Power Turbine Shaft/Torque Reference Tube Magnetic Insert Braze Inspection TABLE 3 - AFFECTED P/N 5128T51G01 POWER TURBINE DRIVE SHAFT ASSEMBLY SERIAL NUMBERS GATHFHH3 GATHNWFN GATJ2FCK GATJ9H9G GATJ9PPM GATJAD50 GATHGG2L GATHT8MK GATJ2NFJ GATJ9H9H GATJ9PPN GATJAECH GATHH5RF GATHTPKA GATJ2WFF GATJ9J3C GATJ9PPR GATJAED3 GATHH77F GATHTPKC GATJ30J6 GATJ9JEK GATJ9PPT GATJAED4 GATHHW3H GATHW0N4 GATJ38KR GATJ9JH2 GATJ9PT1 GATJAEKL GATHHWD8 GATHWER9 GATJ3L67 GATJ9JH3 GATJ9R69 GATJAFHC GATHJD7E GATHWLPE GATJ48TT GATJ9JHG GATJ9R6A GATJAG0M GATHJD7FE GATHWLPF GATJ8T68 GATJ9JJJ GATJ9R8K GATJAJ6P GATHJFRL GATJ06RA GATJ9EHF GATJ9JJK GATJ9RE3 GATJAJM5 GATHJM6F GATJ0AF4 GATJ9EP8 GATJ9KCK GATJA13N GATJAKF8 GATHJM6J GATJ0D98 GATJ9EP9 GATJ9KCL GATJA3FR GATJAL86 GATHJWHD GATJ0HE7 GATJ9EPD GATJ9KCM GATJA47R GATJAT3E GATHK12C GATJ1H07 GATJ9F0H GATJ9KCN GATJA56G GATJC0EM GATHKHDD GATJ1J3L GATJ9F0L GATJ9PLA GATJA6HA GATJC49W GATHKN4K GATJ1JPN GATJ9F0M GATJ9PLC GATJACRE GATJC4A0 GATHKW5L GATJ1JPP GATJ9GMC GATJ9PLD GATJAD07 GATJC4A1 GATHLAWR GATJ1M2L GATJ9GN1 GATJ9PLE GATJAD4W GATJC4G2 GATHLG9J GATJ23MP February 26, 2024 CT7-8 S/B 72-A0118 Revision 01, February 26, 2024 PAGE 13 GE Desi gnated: - CONFIDENTIAL Subject to the restrictions on the media --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). 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