# General Electric Alert Service Bulletin 72-A0335: Revision R02 - Rights: © General Electric Company. Filed by the FAA in regulations.gov docket FAA-2019-0919; AD 2021-18-13 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [General Electric Alert Service Bulletin 72-A0335](https://openairdocs.org/service-documents/ge/72-a0335.md) - Title as filed: CF34-8C Alert SB 72-A0335 R02 - Pages: 8 - PDF: https://openairdocs.org/files/sha256/e9/14/e914984e21189e455c0f78752ef654c685f554093c794f45c4cfb1072e80ba3a - Page: https://openairdocs.org/service-documents/ge/72-a0335/file/e914984e2118 ## 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 CF34-8C Service Bulletins (SBs) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell Date Printed: 2021/06/16 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 8 CF34-8C ALERT SERVICE BULLETIN - 72- A0335 R02 Revised:02/25/2020 SB 72-A0335 R02 ENGINE - COMBUSTION CHAMBER LINER ASSEMBLY (72-44-00) - BORESCOPE INSPECTION OF COMBUSTION OUTER LINER SHELL Issued: 06/27/2019 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. Copyright (2020) General Electric Company, U.S.A. TRANSMITTAL INFORMATION REVISION 2 TO ALERT SERVICE BULLETIN 72-A0335 Revision 2 is issued to update paragraphs 1., and 3., PLANNING INFORMATION .ACCOMPLISHMENT INSTRUCTIONS Revision 1 was issued September 23, 2019. The original was issued June 27, 2019. Revision bars in the left margin identify changes. 1. PLANNING INFORMATION A. Effectivity * * * CF34-8C1/-8C5/-8C5B1 This Alert Service Bulletin is applicable to all CF34-8C engines. The outer shell combustion liners (combustion outer liner shells) P/N , P/N , and P/N are affected by this Alert4124T04G04 4124T04G05 5159T35G02 Service Bulletin. B. Description This Alert Service Bulletin provides instructions to do a repetitive borescope inspection (BSI) of an affected combustion outer liner shell panel P4 with more than 17,500 flight hours time since new (TSN) or time since repair (TSR) per GEK 105091, 72-44-06, REPAIR 023. NOTE:If it is not possible to determine the TSN or TSR of the combustion outer liner shell, engine flight hours since new must be used. C. Compliance Category 2 (1) For engines with combustion outer liner shells that have accumulated more than 17,500 flight hours TSN/TSR at the original Alert Service Bulletin issue date (June 27, 2019), GE recommends that you do the first inspection as soon as possible without effect on revenue service, but before 500 flight hours from the original Alert Service Bulletin issue date. (2) For engines with combustion outer liner shells that have not accumulated more than 17,500 flight hours TSN/TSR at the original Alert Service Bulletin issue date (June 27, 2019), GE recommends that you do the first inspection when the combustion outer liner shell reaches 17,500 flight hours TSN/TSR, or as soon as possible without effect on revenue service, but before 500 flight hours (before 18,000 flight hours TSN/TSR). (3) For engines with combustion outer liner shells that have accumulated more than 17,500 flight hours TSN/TSR, repeat the inspection every 500 flight hours following the inspection criteria defined in Table 1 of paragraph 3., , until theACCOMPLISHMENT INSTRUCTIONS combustion outer liner shell is either repaired per GEK 105091, 72-44-06, REPAIR 023 or ### Page 2 CF34-8C Service Bulletins (SBs) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell Date Printed: 2021/06/16 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 8 replaced with a new combustion outer liner shell at which time the combustion outer liner shell time is reset to zero flight hours. Follow the on-wing inspection recommendation defined in the latest version of CF34-8C S/B until the new/repaired combustion71-0000 outer liner shell reaches 17,500 flight hours again and then repeat this Alert Service Bulletin. NOTE:It is only possible to reset the life of the combustion outer liner shell life by performing GEK 105091, 72-44-06, REPAIR 023. The examples that follow must be taken into consideration: *Example 1: A combustion outer liner shell with 19,000 flight hours TSN is inspected at piece-part level (GEK 105091, 72-44-06, INSPECTION) in the overhaul shop and found to be serviceable (GEK 105091, 72-44-06, REPAIR 023 was not performed). This engine must remain on a 500-hour reduced BSI interval as defined in this Alert Service Bulletin. *Example 2: A combustion outer liner shell with 19,000 flight hours TSN is sent to the component repair shop where GEK 105091, 72-44-06, REPAIR 023 was performed. This engine must follow the on-wing inspection recommendations defined in CF34-8C S/B .71-0000 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 as part of a normally scheduled BSI of the combustor liner assembly. NOTE:This Service Bulletin can be accomplished in shop via BSI or visual inspection of the combustion outer liner shell (hot side/flow path) after the combustor liner assembly is removed from the engine. This Alert 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 Alert 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 reduce significant events. (2) Condition: Ten CF34-8 engines have experienced an unscheduled engine removal (UER) due to significant distress in the combustion outer liner shell, resulting in buckling/material loss of the combustion outer liner shell ( Three of the 10 engines suffered an operationalFigure 1). event, including two engines that had an IFSD due to severe thermal distress of the high pressure turbine (HPT)/low pressure turbine (LPT) hardware including burn through of the LPT case (Figure 2). (3) Cause: The root cause evaluation shows that an axial crack can initiate at the trailing edge (TE) of the combustion outer liner shell panel P4, propagate across the combustion outer liner shell panel P3 into the combustion outer liner shell panel P2 ( and thenFigure 3), connect to a circumferential crack on the combustion outer liner shell panel P2, causing buckling ( of the combustion outer liner shell as well as oxidation of largeFigure 1) sections of it (Figure 5). (4) Inspection: A BSI of the combustion outer liner shell panel P4 is defined to detect and monitor the onset of distress. (5) Substantiation: Substantiation is by fleet experience. 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 Alert Service Bulletin. G. Manpower After you get access to the engine, you will need approximately 3 man-hours for each engine or component. NOTE:For on-wing engines, you will need approximately 3 man-hours after the engine has cooled down. H. Weight and Balance Weight and balance are not changed. I. References (Use the latest version of these documents) GEK 105091, CF34-8C Engine Manual (EM) GEK 105091-1, CF34-8C Line Maintenance Manual (LMM) GEK 105092, CF34-8C Illustrated Parts Catalog (IPC) ### Page 3 CF34-8C Service Bulletins (SBs) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell Date Printed: 2021/06/16 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 8 CF34-8C S/B , POWERPLANT - General (71-00-00) - Consolidated On-Wing71-0000 Inspection Recommendations and Servicing Tasks List J. Publications Affected GEK 105091, CF34-8C Engine Manual (EM) GEK 105091-1, CF34-8C Line Maintenance Manual (LMM) 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: None. B. Industry Support Information None. C. Configuration Chart None. D. Parts Disposition None. E. Tooling - Price and Availability None. 3. ACCOMPLISHMENT INSTRUCTIONS A. Inspection (1) For a description and the locations of the borescope ports, refer to GEK 105091-1, 72-00-00, INSPECTION 003, Subtask 72-00-00-210-002. (2) Remove the high-voltage igniters from the combustion chamber frame as follows: (a) Remove the high-voltage igniter from S16. Refer to GEK 105091-1, 74-00-00, SPECIAL PROCEDURES 009. (b) Remove the high-voltage igniter from S17. Refer to GEK 105091-1, 74-00-00, SPECIAL PROCEDURES 008. (3) Set the light source ON/OFF switch to the ON position and turn the brightness switch from the L position to the H position. (4) Put the flexible borescope probe into S16 and examine the combustion outer liner shell. Refer to Table 1 for inspection limits and do as follows: NOTE:It is not necessary to examine the other features of the combustor liner assembly (combustion inner liner shell or combustor baffles included). Table 1. Combustion Outer Liner Shell - BSI Limits Inspection Inspection Interval Axial (non-circumferential) crack can be connected with circumferential crack. If you do not find cracks on panel P4 of the combustion outer liner shell, do a repetitive BSI at an interval of 500 hours. Refer to Figure 3. For any length of crack on panel P4 of the combustion outer liner shell, do a repetitive BSI at an interval of 500 hours. Refer to Figure 3. If a crack on the combustion outer liner shell connects across the entire length of panel P4 into panel P3, increase the frequency of the BSI to intervals of 300 hours. Refer to Figure 3. If a crack on the combustion outer liner shell connects across the entire length of panels P4 and P3 and goes into panel P2, send the engine to an overhaul facility to replace or repair the combustion outer liner shell within 5 hours in accordance with GEK 105091, 72-44-06, REPAIR 023. Refer to Figure 3. NOTE:Figure 4 shows an example of a combustion outer liner shell panel P4 with no cracks. NOTE:Figure 3 shows a schematic of the combustion outer liner shell with axial crack examples. (a) For all other inspection criteria, refer to GEK 105091-1, 72-00-00, INSPECTION 003, Table 805. (5) Put the flexible borescope probe into S17 and examine the combustion outer liner shell. Refer to Table 1 for inspection limits. ### Page 4 (OCR) CF34-8C Service Bulletins (SBS) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell NOTE: It is not necessary to examine the other features of the combustor liner assembly (combustion inner liner shell or combustor baffles included). (6) Install the high-voltage igniter into the S16 igniter port. Refer to GEK 105091-1, 74-00-00, SPECIAL PROCEDURES 009. (7) Install the high-voltage igniter into the S17 igniter port. Refer to GEK 105091-1, 74-00-00, SPECIAL PROCEDURES 008. 06/23/2017 11:36 257 OLYMPUS 6002802-00 Combustion Outer Liner Shell Buckling on Panel P4 Figure 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 2021/06/16 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 4 of 8 Person, without USG authorization, is strictly prohibited. ### Page 5 (OCR) CF34-8C Service Bulletins (SBS) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell 6002804-00 LPT Case Burn Through 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 2021/06/16 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 5 of 8 Person, without USG authorization, is strictly prohibited. ### Page 6 (OCR) CF34-8C Service Bulletins (SBS) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell ANY LENGTH OF AN AXIAL CRACK ON COMBUSTION OUTER LINER SHELL PANEL P4 (REFER TO NOTE 1) AXIAL CRACK ON COMBUSTION OUTER LINER SHELL THAT EXTENDS ENTIRELY ACROSS PANEL P4 INTO PANEL P3 (REFER TO NOTE 2) AXIAL CRACK ON COMBUSTION OUTER LINER SHELL THAT EXTENDS ENTIRELY ACROSS PANEL P4 AND PANEL P3 INTO PANEL P2 (REFER TO NOTE 3) P4 P2 P1 PO 1. DISPOSITION: SERVICEABLE WITH A 500-HOUR REDUCED BSI INTERVAL. 2. DISPOSITION: SERVICEABLE WITH A 300-HOUR REDUCED BSI INTERVAL. 3. DISPOSITION: UNSERVICEABLE, THE ENGINE MUST BE RETURNED TO AN OVERHAUL FACILITY TO REPLACE THE APPLICABLE HARDWARE WITHIN 5 HOURS. 4. FOR OTHER COMBUSTION OUTER LINER SHELL DISTRESS CONDITIONS NOT SHOWN IN FIGURE 3, YOU CAN USE GEK 105091-1, 72-00-00, INSPECTION 003, TABLE 805 AS REFERENCE. 6002805-01 Combustion Outer Liner Shell Figure 3 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Pag‹ 2021/06/16 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 6 Of Person, without USG authorization, is strictly prohibited. ### Page 7 (OCR) CF34-8C Service Bulletins (SBS) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell 6002803-00 Combustion Outer Liner Shell Panel P4 (No Cracks) Figure 4 GE PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Page 2021/06/16 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 7 of 8 Person, without USG authorization, is strictly prohibited. ### Page 8 (OCR) CF34-8C Service Bulletins (SBS) SB 72-A0335 R02 ENGINE - Combustion Chamber Liner Assembly (72-44-00) - Borescope Inspection of Combustion Outer Liner Shell 6002806-00 Combustor Outer Liner Shell Missing Material Figure 5 GE Designated: - CONFIDENTIAL Subject to the restrictions on the media PROPRIETARY INFORMATION - Not to be used, disclosed to others or Date Printed: reproduced without the express written consent of GE. Technical data Page 2021/06/16 considered ITAR and/or EAR controlled; transfer of this data to a Non-US 8 of 8 [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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