LIST OF EFFECTIVE PAGES The effective pages to this Service Bulletin are as follows: Page Revision Number Revision Date

Bulletin 1 Mar.23/12 2 Mar.23/12 3 Mar.23/12 4 Mar.23/12 5 Mar.23/12 6 Mar.23/12 7 Mar.23/12 8 Mar.23/12 9 Mar.23/12 10 Mar.23/12 11 Mar.23/12 12 Mar.23/12 Appendix 1 1 Mar.23/12**Printed in Great Britain**



# RB.211−72−AG871 Transmittal - Page 21. Planning Information A. Effectivity Airbus A380 RB211 TRENT 970-84 Engines incorporating SB72-G585 (see 1.I., References) RB211 TRENT 970B-84 Engines incorporating SB72-G585 RB211 TRENT 972-84 Engines incorporating SB72-G585 RB211 TRENT 972B-84 Engines incorporating SB72-G585 RB211 TRENT 977-84 Engines incorporating SB72-G585 RB211 TRENT 977B-84 Engines incorporating SB72-G585 RB211 TRENT 980-84 Engines incorporating SB72-G585
B. Reason Problem RB211 Trent 900 engines to pre SB72-G585 standard have been found at overhaul to exhibit varying degrees of fretting wear at the IP coupling spherical abutment within the internal gearbox. Non-Modification Service Bulletin (NMSB) 72-AG329 defines an inspection to monitor wear in service. A package of design changes is introduced by SB72-G585 to resolve the fretting wear issue. In summary, the content of the change package is as follows: (1) The helix angle of the splined joint that connects the IP turbine shaft to the IP compressor rear stubshaft is increased from 10.54 degrees to 18.55 degrees to reduce the IP turbine end-load that is reacted at the spherical abutment. (2) The detail design of the coupling is modified to improve mass distribution within the part to minimise the circumferential variation in local abutment contact pressure under running conditions. (3) The oil/air mist system that is currently used for lubricating the abutment faces is superseded by a new flowing oil-bath arrangement. It is necessary to continue monitoring engines incorporating SB72-G585 until such time as the efficacy of the modification in the service environment has been confirmed. ENGINE - IP TURBINE - BORESCOPE INSPECTION OF IP TURBINE BLADES FOR AXIAL DISPLACEMENT - NON-MODIFICATION SERVICE BULLETIN, NON - MOD.72-AG871**Printed in Great Britain**



# RB.211−72−AG871 Page 1 of 12 Mar.23/12 Mar.23/12C. Description This NMSB instructs a borescope inspection to determine the distance from the face of the IP turbine seal segments and the front seal fin of the IP turbine blades to demonstrate the efficacy of the modification in the service environment. Inspection results (see Appendix 1) must be sent to Rolls-Royce via your local service representative within ten working days of NMSB completion. D. Compliance
ALERT The inspections for IP turbine shaft coupling spline wear must be carried out for all Trent 900 engine variants listed in 1.A. Effectivity in accordance with Section 3., Accomplishment Instructions, of this NMSB as follows: (1) On-wing - Carry out the action specified in 3.A. On-wing borescope inspection, as follows: (a) Carry out an initial inspection before the IP coupling has achieved 400 cycles since new. (b) Repeat inspections intervals must not exceed 400 cycles since the last inspection or since the last shop visit, whichever is applicable. (2) At shop visit - Carry out the action specified in 3.B. Shop visit inspection for all engines. (a) Carry out an inspection in accordance with 3.B.(1) of this NMSB if the IP turbine shaft and IP coupling are exposed during the shop visit. (b) Carry out an inspection in accordance with 3.B.(2) of this NMSB if the IP turbine shaft and IP coupling are not exposed during the shop visit. E. Approval The technical content of this Non-Modification Service Bulletin was approved under the authority of EASA Design Organisation Approval No.EASA.21J.035 on Mar.23/12. This Service Bulletin is subject to the incorporation requirements of an EASA Airworthiness Directive. F. Manpower Estimated man-hours:**Printed in Great Britain**



# RB.211−72−AG871 Page 2 Mar.23/12 Mar.23/12(1) In Service: (a) Time to gain access - 0.5 hour (1 person) (b) Time to inspect - 0.5 hour (1 person) (excludes engine cooling time) (c) Time to restore to serviceable condition - 0.5 hour (1 person) (2) In Shop No additional manpower G. Material Price and Availability Not applicable H. Tooling Flexible, 6mm diameter borescope with forward facing stereo measurement tip. The borescope inspection equipment must have image capture capability. I. References (1) Rolls-Royce RB211 Service Bulletin: 72-G585 Engine - IP turbine shaft - Introduction of a 52 spline IP turbine shaft and revised IP compressor rear shaft and coupling assembly (2) Engine Manual Task 72-00-00-200-835 (3) Cleaning, Inspection and Repair Manual: (a) Task 72-33-21-200-804 (b) Task 72-51-33-200-801 (4) Maintenance Manual, Task 72-00-00-200-807-A (5) Engine Illustrated Parts Catalogue (EIPC) 72-51-23-01-290 2. Material Information Not applicable 3. Accomplishment instructions**Printed in Great Britain**



# RB.211−72−AG871 Page 3 Mar.23/12 Mar.23/12A. On-wing Borescope Inspection

WARNING : YOU MUST BE CAREFUL WHEN YOU WORK ON THE ENGINE AFTER THE ENGINE IS SHUTDOWN. THE ENGINE CAN STAY HOT FOR ALMOST ONE HOUR.
WARNING : YOU MUST NOT TOUCH HOT PARTS WITHOUT APPLICABLE GLOVES. HOT PARTS CAN CAUSE AN INJURY. IF YOU GET AN INJURY PUT IT IN COLD WATER FOR 10 MINUTES AND GET MEDICAL AID.
CAUTION : IN ORDER TO REDUCE THE POTENTIAL FOR MULTIPLE ENGINE IN FLIGHT SHUTDOWN, POWER LOSS OR OTHER ANOMALIES DUE TO MAINTENANCE ERROR, ROLLS-ROYCE RECOMMENDS THAT OPERATORS AVOID PERFORMING MAINTENANCE ON MULTIPLE ENGINES INSTALLED ON THE SAME AIRCRAFT AT THE SAME TIME. IF IT IS NOT POSSIBLE TO AVOID MAINTENANCE ON MORE THAN ONE ENGINE AT THE SAME TIME, ROLLS-ROYCE RECOMMENDS THAT ADDITIONAL CONTROLS ARE APPLIED IN ORDER TO ENSURE THAT MAINTENANCE TASKS HAVE BEEN COMPLETED AS DEFINED. MAINTENANCE GUIDELINES SHOULD BE REVISED, WHERE POSSIBLE, TO PROMOTE THIS RECOMMENDATION.
CAUTION : DO NOT START THE BORESCOPE INSPECTION UNTIL THE ENGINE HAS COOLED TO WITHIN THE BORESCOPE MANUFACTURERS RECOMMENDATIONS. THE ENGINE IS HOT IMMEDIATELY AFTER THE ENGINE IS STOPPED AND CAN CAUSE BURNS AND DAMAGE TO BORESCOPE INSPECTION EQUIPMENT. (1) Gain access: Prepare the engine for inspection as would be done for borescope inspection of the IP turbine blades in accordance with Aircraft Maintenance Manual (AMM) Task 72-00-00-200-807-A. This will allow access to the borescope blanking plug EIPC Fig/Item No.72-51-23, 01-290. See Figure 1. (2) Perform Borescope Inspection (using flexible 6mm outer diameter borescope, with forward facing stereo measurement tip): (a) Insert flexible borescope through the IP turbine borescope port. Once the end is in the gas path, direct the borescope rearwards towards the IP turbine blades as shown in Figure 3a.
NOTE : The use of a guide tube to assist the passage of the borescope from the access port to the IP turbine blades may be useful. Guide tube can be locally sourced. Details including desired shape and dimensions are shown in Figure 2. (b) Adjust the angle of the borescope end until a clear view of the IP turbine seal segment and IP turbine blade seal fin is achieved as shown in Figure 3b.**Printed in Great Britain**



# RB.211−72−AG871 Page 4 Mar.23/12 Mar.23/12(c) Using the stereo forward facing lens on the borescope, manipulate the borescope to be as close as possible to the diamond patterned surface of the seal segment. (d) Capture an image of the area shown in Figure 3b. If necessary repeat steps (b) and (c), above. (e) A cross-section showing the IP turbine seal segment and IP turbine blade seal fin, together with the datum and measurement points, is shown in Figure 4. Measure length 'B' as shown in Figure 5 using the 'point-to-line' measurement. The measurement is to be taken approximately in the middle of the shroud of one of the IP turbine blades and probe to object distance (value 'Z') is to be no more than 15 mm (0.59 in.). The measurement must be recorded in millimeters. (f) Repeat the above inspection two more times for different 'Z' values but the probe to object value is not to be more than 15 mm (0.59 in.). (g) Provide all three inspection results and photographs in accordance with 3.C., below. (3) Acceptance Limits: (a) Dimension B is not greater than 6,00 mm Repeat this inspection every 400 cycles (b) Dimension B is greater than 6,00 mm and less than 8,00 mm Remove the engine within 10 flights

(c) Dimension B is 8,00 mm or greater Remove the engine immediately

(4) Close up: (a) Apply with a brush a thin layer of OMat 4/62 Anti-seize compound to the borescope blanking plug EIPC Fig/Item No.72-51-23, 01-290 (b) Install the borescope blanking plug EIPC Fig/Item No.72-51-23, 01-290. (c) Torque tighten the borescope blanking plug EIPC Fig/Item No.72-51-23, 01-290 to 2,6 m.daN (230 lbfin). (d) Restore the engine for service operation in accordance with AMM Task 72-00-00-200-807-A Borescope Inspection of the IP Turbine Blades**Printed in Great Britain**



# RB.211−72−AG871 Page 5 Mar.23/12 Mar.23/12B. Shop visit Inspection: (1) If the IP turbine shaft (EIPC Fig/Item No.72-51-33, 01-185) and IP coupling (EIPC Fig/Item No.72-33-21,01-415) are exposed during engine disassembly: (a) Inspect the IP turbine shaft in accordance with Cleaning, Inspection and Repair (CIR) Manual Task 72-51-33-200-801 (b) Inspect the IP coupling in accordance with CIR Manual Task 72-33-21-200-804 (c) Provide inspection results and photographs in accordance with 3.C., below (2) If the IP turbine shaft (EIPC Fig/Item No.72-51-33, 01-185) and IP coupling (EIPC Fig/Item No.72-33-21,01-415) are not exposed during engine disassembly then carry out a borescope inspection as follows: (a) Gain access Prepare the engine for inspection as would be done for borescope inspection of the IP turbine blades in accordance with Engine Manual (EM) Task 72-00-00-200-835. The borescope blanking plug EIPC Fig/Item No.72-51-23, 01-290 is shown in Fig. 1. (b) Perform borescope inspection (using flexible 6mm outer diameter borescope, with forward facing stereo measurement tip) in accordance with 3.A.(2)(a) to (f) of this NMSB (c) Provide all three inspection results and photographs in accordance with 3.C., below (d) If Dimension B is not greater than 6,00 mm the engine may be returned to service. The next borescope inspection must be carried out at no more than 400 cycles since this shop visit (e) If Dimension B is greater than 6,00 mm then the IP turbine shaft and IP coupling must be inspected in accordance with Cleaning, Inspection and Repair Manual Task 72-51-33-200-801 and Task 72-33-21-200-804 respectively (f) On completion of the borescope inspection, install the borescope blanking plug, EIPC Fig/Item No.72-51-23, 01-290 in accordance with EM Task 72-00-00-200-835**Printed in Great Britain**



# RB.211−72−AG871 Page 6 Mar.23/12 Mar.23/12C. Inspection results Forward the inspection results and photographs showing the measurement result to Rolls-Royce, via your assigned Service Representative, within ten working days of completion of on-wing or in-shop inspections as stated below and in Appendix 1. (1) On-wing Forward the inspection results and photographs showing the actual dimensions recorded for dimension 'B' as shown in Figure 5. Use Feedback Sheet provided in Appendix 1. (2) In-shop (a) For IP turbine shafts and IP couplings exposed during engine disassembly Complete the details of engine and coupling information for the engine being inspected. Obtain photographs of the abutment face surfaces on the IP turbine shaft and IP coupling, even if there is no wear evident. Use Feedback Sheet provided in Appendix 1. (b) For IP turbine shafts and IP couplings not exposed during engine disassembly Forward the inspection results and photographs showing the actual dimensions recorded for Dimension B as shown in Figure 5. Use Feedback Sheet provided in Appendix 1.**Printed in Great Britain**



# RB.211−72−AG871 Page 7 Mar.23/12 Mar.23/12

## B 1 IP TURBINE BORESCOPE BLANKING PLUGdeh0005740 

## A



## A **B**

IP turbine borescope access blanking plug Fig. 1**Printed in Great Britain**



# RB.211−72−AG871 Page 8 Mar.23/12 Mar.23/12Guide tube to assist passage of borescope from access port to IP turbine blades Fig.2**Printed in Great Britain**



# RB.211−72−AG871 Page 9 Mar.23/12 Mar.23/12IP turbine seal segment and IP turbine blade seal fin Fig.3**Printed in Great Britain**



# RB.211−72−AG871 Page 10 Mar.23/12 Mar.23/12 

### Fig 3 a Zoomed out view showing stereo images of an IP turbine seal segment and IP turbine blade seal fin as viewed through forward facing stereo measurement tip Viewed looking engine forward IP Turbine Blades

IP Turbine Seal Segments

IP Turbin e Blade front seal fin (measured point)

Fig 3 b Close up view showing stereo images of an IP turbine seal segment and IP turbine blade seal fin as viewed through forward facing stereo measurement tip Viewed looking engine forward IP Turbine Seal Segment front face (datum) IP Turbine Blade front seal fin (measured point)IP turbine seal segment and IP turbine blade Fig.4**Printed in Great Britain**



# RB.211−72−AG871 Page 11 Mar.23/12 Mar.23/12 

### Fig 4 Showing cross section of the IP turbine seal segment and IP turbine blade Dimension B IP Turbine Seal Segment front face (datum) IP Turbine Blade front seal fin (measured point)

Viewed lookin g engine rearwardIP turbine seal segment and IP turbine blade seal fin - Measurement of Length B Fig.5**Printed in Great Britain**



# RB.211−72−AG871 Page 12 Mar.23/12 Mar.23/12



### Figure 5 showing the 'point- to

- line' measurement being used to measure Length B from the end face of the seal segment to the front seal fin of the IP Turbine Blades IP Turbine Seal Segment front face (datum) IP Turbine Blade front seal fin (measured point)

Viewed looking engine forwardNon-Modification Service Bulletin 72-AG871 - Inspection Results 1. Borescope inspection findings (In-shop and On-wing) Complete the details of Engine and Coupling information for the engine being inspected, record the actual measurement result (Length B) and the photograph(s) taken showing the measurement result to Rolls-Royce, via your assigned Service Representative, within ten working days of NMSB completion. 2. Piece part inspection findings: Complete the details of Engine and Coupling information for the engine being inspected. Obtain photographs of the abutment face surfaces on the IPT shaft and IP coupling, even if there is no wear evident. Send these photographs together with the inspection findings to Rolls-Royce, via your assigned Service Representative, within ten working days of NMSB completion.

NMSB 72-AG871 Feedback Sheet Overhaul Base Operator Date of Inspection Engine Serial No. Engine Hours Since New Engine Cycles Since New

IP Coupling Part No. IP Coupling Serial No. IP Coupling Hours Since New IP Coupling Cycles Since New

Inspection Result (Accept/Reject) and Comments Borescope inspection (In-shop and On-Wing): Record Length 'B' (see Fig.4) Piece part inspection: Record the amount of wear to the IP Coupling and IP Turbine Shaft abutment faces APPENDIX 1**Printed in Great Britain**



# RB.211−72−AG871 Appendix 1 - Page 1 of 1 Mar.23/12 Mar.23/12