# General Electric Service Bulletin CT7-TP: No revision named - Rights: © General Electric Company. Filed by the FAA in regulations.gov docket FAA-2022-1314; AD 2023-21-07 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [General Electric Service Bulletin CT7-TP](https://openairdocs.org/service-documents/ge/ct7-tp.md) - Title as filed: GE Service Bulletin CT7-TP 72-0541 R01 - Pages: 7 - PDF: https://openairdocs.org/files/sha256/e6/e5/e6e5ec12220e426678872867089949c526f091cf6aeef4e565160637df6fca26 - Page: https://openairdocs.org/service-documents/ge/ct7-tp/file/e6e5ec12220e ## 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 CT7-TP 9 Service Bulletins (SBs) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft Date Printed: 2021/12/06 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced without the express written consent of GE. Technical data is considered ITAR and/or EAR controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly prohibited. Page 1 of 7 CT7-TP SERVICE BULLETIN - 72-0541 R01 Revised:11/18/2021 SB 72-0541 R01 ENGINE - PROPELLER GEARBOX (72-10-00) - INTRODUCTION OF ULTRASONIC INSPECTION FOR THE PGB MAIN PROPELLER SHAFT Issued: 09/09/2021 GE Designated: -CONFIDENTIAL- The information contained in this document is GE proprietary information and is disclosed in confidence. 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, modifications, spare parts, designs, or configuration 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) pursuant 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. GE Aviation authorizes the Federal Aviation Administration to incorporate this document by reference in an Airworthiness Directive. Copyright (2021) General Electric Company, U.S.A. TRANSMITTAL INFORMATION REVISION 1 TO SERVICE BULLETIN 72-0541 Revision 1 is issued to update paragraph 1., .PLANNING INFORMATION The original was issued September 09, 2021. Revision bars in the left margin identify changes. 1. PLANNING INFORMATION A. Effectivity * * * CT7-5A2/-5A3/-7A/-7A1/-9B/-9B1/-9B2/-9C/-9C3 This Service Bulletin is applicable to all CT7-TP engines. The main propeller shafts VIN (P/N ), VIN (P/N 775801-1 775801G01 775801-2 ), VIN (P/N ), and VIN (P/N ) are775801G02 775801-3 775801G03 775801-4 775801G04 affected by this Service Bulletin. B. Description This Service Bulletin introduces an ultrasonic inspection (UTI) and enhanced inspection plan for the affected main propeller shafts. C. Compliance Category 2 GE recommends that you do the initial and repetitive inspections of this Service Bulletin after reaching the inspection threshold and within the repeat intervals in Table 1 or Table 2 below. Table 1. CT7-5/-9B Inspection Threshold and Interval Engine Model Inspection Threshold [Cycles Since New (CSN)] First Inspection Repeat Interval [Every Flight Hours (EFH)] Visual inspection 0 At first propeller removal At every propeller removal Fluorescent penetrant inspection (FPI) 20,000 Within 2,100 flight hours (FH) since issue date of this Service Bulletin At every propeller removal or 2,100 FH, whichever is greater. ### Page 2 CT7-TP 9 Service Bulletins (SBs) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft Date Printed: 2021/12/06 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced without the express written consent of GE. Technical data is considered ITAR and/or EAR controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly prohibited. Page 2 of 7 CT7-5/-9B initial revision,after reaching threshold Ultrasonic Inspection (UTI) 20,000 Within 1,600 FH since issue date of this Service Bulletin initial revision, after reaching threshold 5,000 FH NOTE:If the main propeller shaft CSN information is unknown, inspection schedule must be based on the propeller gearbox (PGB) CSN. If the PGB CSN information is unknown, it must be assumed that the inspection threshold is exceeded. Table 2. CT7-7/-9C/-9C3 Inspection Threshold and Interval Engine Model Inspection Threshold [Cycles Since New (CSN)] First Inspection Repeat Interval [Every Flight Hours (EFH)] CT7-7/-9C/-9C3 Visual inspection 0 At first propeller removal At every propeller removal Fluorescent penetrant inspection (FPI) 20,000 Within 2,400 FH since issue date of this Service Bulletin initial revision, after reaching threshold At every propeller removal or 2,400 FH, whichever is greater. Ultrasonic Inspection (UTI) 20,000 Within 1,600 FH since issue date of this Service Bulletin initial revision, after reaching threshold 4,800 FH NOTE:If the main propeller shaft CSN information is unknown, inspection schedule must be based on the propeller gearbox (PGB) CSN. If the PGB CSN information is unknown, it must be assumed that the inspection threshold is exceeded. Impact B This recommendation is to address a condition that may result in an Increased Rate of In-Flight Shutdowns (IFSD), Take-Off Aborts (TOA), Air Turn Backs (ATB) or Diversions (DIV). NOTE:This Service Bulletin can be accomplished on wing or in shop. The main propeller shaft may be installed on or removed from the PGB. This Service Bulletin is offered to improve the reliability or performance of your GE product, or to help prevent the occurrence of the event or condition described in this Service Bulletin. If the operator elects not to participate in the bulletin, that decision will be taken into consideration by GE in evaluating future product performance issues that may arise in the operator's fleet. D. Concurrent Requirements None. E. Reason (1) Objective: To improve reliability. (2) Condition: The main propeller shaft requires an enhanced inspection of the dowel pin holes to detect possible cracks. (3) Cause: Corrosion can initiate a crack inside the two dowel pin holes of the main propeller shaft. (4) Inspection: The enhanced inspection plan provides a method to detect possible crack initiation in the dowel pin holes before reaching the forward face of the shaft flange. (5) Substantiation: Substantiation is by fleet experience and test. F. Approval The data contained in this Service Bulletin has been reviewed by the FAA or authorized entity representing the FAA and the repair(s) and modification(s) herein comply with the applicable Aviation Regulations and are APPROVED for installation in the model(s) listed in this Service Bulletin. G. Manpower After you get access to the main propeller shaft, you will need approximately 1 man-hour for each engine or component. ### Page 3 CT7-TP 9 Service Bulletins (SBs) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft Date Printed: 2021/12/06 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or reproduced without the express written consent of GE. Technical data is considered ITAR and/or EAR controlled; transfer of this data to a Non-US Person, without USG authorization, is strictly prohibited. Page 3 of 7 H. Weight and Balance Weight and balance are not changed. I. References (Use the latest version of these documents) GEK 9250, Commercial Engine Standard Practices Manual (SPM) SEI-576, CT7 Maintenance Manual (MM) SEI-577, CT7-5/-7 Illustrated Parts Catalog (IPC) SEI-663, Component Maintenance Manual (CMM), 72-11-02 SEI-723, CT7-9 Illustrated Parts Catalog (IPC) J. Publications Affected None. K. Interchangeability Not applicable. L. Software Accomplishment Summary Not applicable. 2. MATERIAL INFORMATION A. Material - Price and Availability (1) Parts necessary to do this Service Bulletin: None. (2) Other Spare Parts: None. (3) Consumables: Refer to SEI-576, 72-10-00, SPECIAL PROCEDURE 005. B. Industry Support Information None. C. Configuration Chart None. D. Parts Disposition None. E. Tooling - Price and Availability Tool Number Description GE-FQAP-769* Ultrasonic Inspection Kit *The ultrasonic inspection kit GE-FQAP-769 can be ordered at ndttooling@ge.com. 3. ACCOMPLISHMENT INSTRUCTIONS A. General (1) Remove the propeller assembly to get access to the main propeller shaft ( ReferFigure 1). to the applicable aircraft manufacturer manual. (2) If installed, remove the shim (gasket) from between the propeller hub and main propeller shaft ( flange. Refer to the applicable propeller manufacturer documentation.Figure 1) B. Cleaning (1) Clean the main propeller shaft ( flange. Refer to SEI 576, 72-10-00, CLEANING.Figure 1) C. Inspection (1) Do a visual inspection as follows: (a) Do a general visual inspection of the exposed main propeller shaft ( ReferFigure 1). to SEI 576, 72-10-00, INSPECTION. (b) Do a detailed visual inspection of the main propeller shaft ( flange forwardFigure 1) face for wear and corrosion. Refer to SEI 576, 72-10-00, INSPECTION. (c) Do a detailed visual inspection with a 10x magnifier of the main propeller shaft ( forward face of the flange, areas adjacent to the two dowel pin holes.Figure 1) Refer to SEI 576, 72-10-00, INSPECTION. (2) Do an FPI as follows: (a) Do a spot FPI of the main propeller shaft ( forward face of the flange,Figure 1) areas adjacent to the dowel pin holes. Refer to SEI 576, 72-10-00, SPECIAL PROCEDURE 005, and do as follows: 1 Record the inspection results in the FPI Log Sheet (Figure 2). (b) Send the inspection results to the contact information that follows. Include the filled FPI Log Sheet (Figure 2). GE Aviation Fleet Support E-mail: aviation.fleetsupport@ge.com Website: https://my.geaviation.com Attn.: Fleet Engineering, CT7-TP (ATA 72-10-00) PGB Module Leader (3) Do an UTI as follows: (a) Do an UTI of the two dowel pin holes ( Refer to SEI-576, 72-10-00, SPECIALFigure 1). PROCEDURE 005, and do as follows: ### Page 4 (OCR) CT7-TP 9 Service Bulletins (SBS) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft Record the inspection results in the FPI Log Sheet (Figure 3). (b) Send the inspection results to the contact information that follows. Include the filled UTI Log Sheet (Figure 3). GE Aviation Fleet Support E-mail: aviation.fleetsupport@ge.com Website: https://my.geaviation.com Attn.: Fleet Engineering, CT7-TP (ATA 72-10-00) PGB Module Leader MAIN PROPELLER SHAFT PGB MAIN PROPELLER SHAFT FLANGE 6022172-00 Main Propeller Shaft Inspection Figure 1 (Sheet 1) GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Page 2021/12/06 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 4 Of T Person, without USG authorization, is strictly prohibited. ### Page 5 (OCR) CT7-TP 9 Service Bulletins (SBS) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft • DOWEL PIN HOLE _ MAIN PROPELLER SHAFT FWD DOWEL PIN HOLE -DOWEL PIN HOLE A-A DOWEL PIN HOLE FORWARD LOOKING AFT LONGITUDINAL MODE SHEAR MODE - CLOCKWISE (CW) AND COUNTERCLOCKWISE (COW) 6022173-00 Main Propeller Shaft Inspection Figure 1 (Sheet 2) PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Page 2021/12/06 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 5 of 7 Person, without USG authorization, is strictly prohibited. ### Page 6 (OCR) CT7-IP 9 Service Bulletins (SBS) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft FPI LOG SHEET OPERATOR PGB P/N DATE PGB S/N PGB TIME SINCE MAIN PROPELLER NEW (TSN) SHAFT P/N PGB CSN MAIN PROPELLER SHAFT S/N MAIN PROPELLER SHAFT TSN PROPELLER ASSEMBLY MANUFACTURER PIN AND PROPELLER PROPELLER ASSEMBLY SHAFT CSN SHIM TYPE INSPECTION RESULT (ACCEPT / REJECT) OTHER NOTES 6022174-00 FPI Log Sheet Figure 2 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Page 2021/12/06 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 6 of 7 [Person, without USG authorization, is strictly prohibited. ### Page 7 (OCR) CT7-TP 9 Service Bulletins (SBs) SB 72-0541 R01 ENGINE - Propeller Gearbox (72-10-00) - Introduction of Ultrasonic Inspection for the PGB Main Propeller Shaft UTI LOG SHEET OPERATOR: PGB PIN FACILITY: PGB S-N DATE: MAIN PROPELLER SHAFT P/N: PGB TSN: MAIN PROPELLER SHAFT S/N: PGB CSN: MAIN PROPELLER SHAFT BORE DIA MAIN PROPELLER PROPELLER ASSEMBLY PIN SHAFT TSN: AND MANUFACTURER MAIN PROPELLER PROPELLER ASSEMBLY SHAFT CSN: GHIM TYPE LONGITUDINAL CALIBRATION INFORMATION NSTRUMENT: INSTRUMENT S.N: PROBE PIN: PROBE S:N: REFERENCE STANDARD PIN: REFERENCE STANDARD SN: FREQ: CALIBRATION GAIN: RANGE: CALIBRATION DELAY: VELOCITY: REJECT: PRE-CALIBRATION PERCENT: POST-CALIBRATION PERCENT: INSPECTION GAIN: FINAL DELAY SETTING: SHEAR CALIBRATION INFORMATION INSTRUMENT: INSTRUMENT SN: PROBE P/N: PROBE SIN: REFERENCE STANDARD PN: REFERENCE STANDARD SIN: FREO: CALIBRATION GAIN: RANGE: CALIBRATION DELAY: VELOCITY: REJECT: PRE-CALIBRATION PERCENT: POST-CALIBRATION PERCENT INSPECTION GAIN: INDICATION - CLOCK LONG. (S) SHEAR CW V) SHEAR COW (V) PERCENT POSITION BORE ID HOLE NO. 1 DOWEL PIN 6:00 O'CLOCK POSITION 3:00 O'CLOCK 9:00 O'CLOC POSITION POSITION INDICATION - CLOCK LONG. (S SHEAR CW (V) SHEAR CCW (V) PERCENT POSITION BORE ID DOWEL PIN FOOTLOCI HOLE NO. 2 POSITION 3:00 D/CLOCI POSITION POSITION DISPOSITION: _(ACCEPT / REJECT) OTHER NOTES 6022175-00 UTI Log Sheet Figure 3 GE Designated: - CONFIDENTIAL Subject to the restrictions on the media GE PROPRIETARY INFORMATION - Not to be used, disclosed to other: or Date Printed: reproduced without the express written consent of GE. Technical data is Page 2021/12/06 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 7 of 7 Person, without USG authorization, is strictly prohibited. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. 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