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 2
1. 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abutment faces is superseded by a new flowing oil-bath arrangement.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.23/12
C. 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

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(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

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Mar.23/12
A. 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

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(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

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Mar.23/12

Mar.23/12
B. 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

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C. 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

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Mar.23/12
B

1 IP TURBINE

BORESCOPE

BLANKING PLUG

deh0005740

A

A

B

IP turbine borescope access blanking plug

Fig. 1

Printed in Great Britain

RB.211−72−AG871

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Mar.23/12

Mar.23/12
Guide tube to assist passage of borescope from access port to IP turbine blades

Fig.2

Printed in Great Britain

RB.211−72−AG871

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Mar.23/12
IP turbine seal segment and IP turbine blade seal fin

Fig.3

Printed in Great Britain

RB.211−72−AG871

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Fig 3a 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 Turbine Blade front 

seal fin (measured point)

Fig 3b 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

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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 looking engine rearward
IP 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

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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 forward
Non-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