LIST OF EFFECTIVE PAGES

The effective pages to this Service Bulletin are as follows:

Page Revision Number Revision Date

Bulletin

1 Apr.30/13

2 Apr.30/13

3 Apr.30/13

4 Apr.30/13

5 Apr.30/13

6 Apr.30/13

7 Apr.30/13

8 Apr.30/13

9 Apr.30/13

10 Apr.30/13

11 Apr.30/13

12 Apr.30/13

13 Apr.30/13

14 Apr.30/13

15 Apr.30/13

Appendix 1

1 Apr.30/13

2 Apr.30/13

Printed in Great Britain

RB.211−72−AG644

Transmittal - Page 2
1. Planning Information

A. Effectivity

Boeing 777

RB211 TRENT875-17 Engines not incorporating SB72-G604

RB211 TRENT877-17 Engines not incorporating SB72-G604

RB211 TRENT884-17 Engines not incorporating SB72-G604

RB211 TRENT884B-17 Engines not incorporating SB72-G604

RB211 TRENT892-17 Engines not incorporating SB72-G604

RB211 TRENT892B-17 Engines not incorporating SB72-G604

RB211 TRENT895-17 Engines not incorporating SB72-G604

B. Reason

Problem

It has been identified that limitations in the drawing definition for the Trent

800 LP Turbine Bearing Support and Exhaust Case assembly (EIPC 72-52-51,

03-300, also known as the Tail Bearing Housing or TBH) may have resulted in

thin wall section parts being delivered into service. A number of in-service

parts have been measured and analysis of the results suggests that under

certain circumstances the integrity of a thin walled part may be affected

following a Fan Blade Off event. Action has been taken in new production to

prevent manufacture of thin walled parts in the future, therefore this

Non-Modification Service Bulletin (NMSB) will not be applicable to new part

numbers.

C. Description

This NMSB targets two populations of LP Turbine Bearing Support and Exhaust

Case assembly. The first group comprises nine assemblies which have already

been measured during shop visit and subsequently shown to be below desirable

limits. For this first group, the NMSB instructs a one-time rework to the LP

Turbine Bearing Support and Exhaust Case assembly in accordance with SB72-G604

(see 1.I., References) at the next shop visit.

ENGINE - LP TURBINE BEARING SUPPORT AND EXHAUST CASE ASSEMBLY (TAIL BEARING HOUSING)

WALL THICKNESS INSPECTION - NON-MODIFICATION SERVICE BULLETIN - NON - MOD.72-AG644

Printed in Great Britain

RB.211−72−AG644

Page 1 of 15

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The second group comprises the rest of the fleet. For this second group, the

NMSB instructs a one-time in-shop inspection of the LP Turbine Bearing Support

and Exhaust Case assembly for part markings, for hub to conical panel weld

thickness and for hub to conical panel flange thickness (see Fig.1 and Fig.3).

These measurements will be used to determine whether or not rework in

accordance with SB72-G604 is required and will ensure the wall thickness in

both locations is adequate for continued operation.

It is recommended that the required information is recorded during the

inspection in Appendix 1 (or similar form) and kept with the engine records for

possible future use.

Accomplishment of this NMSB must be recorded in the engine and module logbooks.

D. Compliance

(1) On-Wing

Not applicable

(2) In Shop

ALERT

This Non-Modification Service Bulletin is anticipated to be the subject of

an EASA/FAA Airworthiness Directive

Accomplish the actions defined in Section 3., Accomplishment Instructions

as follows:

(a) For Engines which have an LP turbine module (Module 08) with one of

the following Serial Numbers: FM0015, FM0032, FM0104, FM0114, FM9773,

FM9922, FM9925, FM9950, FM9951.

Accomplish the actions defined in 3., Accomplishment Instructions,

Part A, by the earliest of:

(i) At the next Serviceability, Check and Repair, Refurbishment or

Overhaul engine shop visit

(ii) By 30th June 2017.

(b) For Engines which have an LP turbine module (Module 08) with any

Serial Number which is NOT listed at (a), above

Accomplish the actions defined in 3., Accomplishment Instructions,

Part B, by the earliest of:

(i) During shop visit for those engines currently in the shop where

the affected part is exposed and substantial rebuild has not

yet started

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(ii) At the next Refurbishment or Overhaul engine shop visit, or

where the module is sufficiently exposed to carry out the

inspection.

(iii) By 31st December 2020.

E. Approval

The technical content of this Non-Modification Service Bulletin was approved

under the authority of the EASA Design Organisation Approval No.EASA.21J.035 on

Apr.29/13.

F. Manpower

Time to inspect: 1 hour (1 person)

G. Material Price and Availabilty

None

H. Tooling Price and Availability

Special tools are not required

I. References

(1) Rolls-Royce RB211 Service Bulletins:

72-G604 Engine - Exhaust Case - Introduction of a revised LP Turbine

Exhaust Case and Support Assembly featuring an increased

wall thickness of LP Bearing Support flange

(2) Engine Manual, 72-52-51, Cleaning

(3) Engine Overhaul Processes Manual TSD 594-J, Task 70-00-00-300-363, Marking

Methods

(4) Standard Practices Manual, Task 70-42-11-300-001, Repair Minor Damage on

Surfaces

2. Material Information

None

Printed in Great Britain

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3. Accomplishment Instructions

A. LP Turbine Modules with Serial Numbers listed in 1.D., Compliance, Section (2),

(a):

(1) Refer to Fig.1, Fig.2 and Fig.7.

(2) Check the LP Turbine Bearing Support and Exhaust Case assembly (72-52-51,

03-300) part and serial numbers match those given in Fig.7 for the

applicable Module Serial Number

(a) If the identity markings do not match those given in Fig.7, inform

your assigned Rolls-Royce service representative.

(b) If the identity markings match those given in Fig.7, proceed to step

(3), below.

(3) Rework the LP Turbine Bearing Support and Exhaust Case assembly in

accordance with Service Bulletin 72-G604

(4) Mark the part to record accomplishment of NMSB 72-AG644:

(a) Refer to Fig.2.

(b) Refer to Engine Overhaul Processes Manual TSD 594-J, Task

70-00-00-300-363, Marking Methods

(c) Mark NMSB 72-AG644 adjacent to the part number. Use vibration-peen

equipment.

(5) Record the accomplishment of NMSB 72-AG644 in the engine and module

logbooks.

B. LP Turbine Modules with any Serial Numbers which are NOT listed in 1.D.,

Compliance, Section (2), (a):

(1) Clean the part. Refer to Engine Manual, 72-52-51, Cleaning.

(2) Check the part for markings

(a) Refer to Fig.2.

(b) View location of part markings for evidence of the previous

accomplishment of NMSB72-AG644

(c) If there is no part marking of the previous accomplishment of

NMSB72-AG644, then proceed to step (3) of these Accomplishment

Instructions, below.

Printed in Great Britain

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(d) If there is part marking of the previous accomplishment of

NMSB72-AG644, then:

(i) Ensure that accomplishment of this NMSB has been recorded in

the engine and module logbooks

(ii) No further action is required

(3) Measure the LP Turbine Bearing Support and Exhaust Case assembly hub to

conical panel weld line thickness

(a) Refer to Fig.3 and Fig.4.

(b) Check that the weld dressing is smooth and continuous around the

circumference of the part and check that there are no sharp changes in

the profile:

(i) If the weld dressing is not smooth, then lightly dress to a

smooth profile, taking care to avoid thinning the material.

Refer to Standard Practices Manual, Task 70-42-11-300-001,

Repair Minor Damage on Surfaces.

(c) Measure the thickness of the Hub to Conical Panel weld line at eight

circumferential, equispaced locations, begin at the Top Dead Centre

(TDC) and continue in a clockwise direction. Take five measurements at

each location as follows:

(i) One measurement between 11,00mm and 12,00mm (0.433in. and

0.472in.) radially outboard from the centre of the weld

(position Y1).

(ii) One measurement 6,00mm (0.236in.) radially outboard from the

centre of the weld (position Y2).

(iii) One measurement at the centre of the weld (position Y3).

(iv) One measurement 6,00mm (0.236in.) radially inboard from the

centre of the weld (position Y4).

Printed in Great Britain

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(v) One measurement 12,00mm (0.472in.) radially inboard from the

centre of the weld (position Y5).

NOTE: Some LP Turbine Bearing Support and Exhaust Case assemblies

with Part Number FK24251 or FK32232 where chemically etched

at manufacture to thin the material 13mm (0.512in.) from

the weld line. Ensure that the measurement at position Y1

is not taken in an etched thin area by measuring not more

than 12mm (0.472in.) from the centre of the weld line. The

rework specified in SB 72-G604 is effective up to 10,00mm

(0.394in.) from the weld line; for this reason ensure Y1

measurements are not taken less than 11,00mm (0.433in.)

from the centre of the weld line.

(d) Apply the following sentencing criteria to the minimum measurement

from the eight measured locations defined at (c) above:

(i) Minimum thickness at

positions Y1, Y2, Y3, Y4

and Y5 is equal to, or

greater than, 2,52mm

(0.099in.)

Accept

Proceed to step (4), below

(ii) Minimum thickness at

position Y1 is equal to, or

greater than, 2,52mm

(0.099in.) and minimum

thickness at positions Y2,

Y3, Y4 or Y5 is less than,

2,52mm (0.099in.)

Rework in accordance with SB72-G604

Proceed to step (5), below

(iii) Minimum thickness at

position Y1 is less than,

2,52mm (0.099in.)

Reject

Proceed to step (6), below

(4) Measure the LP Turbine Bearing Support and Exhaust Case assembly Hub to

Conical Panel Flange thickness

(a) Refer to Fig.3, Fig.5 and Fig.6.

(b) Measure the thickness 'X' of the Hub to Conical Panel at eight

circumferential, equispaced locations, begin at the Top Dead Centre

(TDC) and continue in a clockwise direction:

(c) Apply the following sentencing criteria to the measurements from the

eight locations defined at (c) above:

(i) Minimum thickness is equal

to, or greater than, 2,20mm

(0.087in.)

Accept

Proceed to step (5), below

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(ii) The thickness at one

location is less than

2,20mm (0.087in.) but is

greater than, or equal to,

2,00mm (0.079in.) and at

all other locations is

equal to, or greater than,

2,20mm (0.087in.)

Accept

Proceed to step (5), below

(iii) The thickness at two

locations, which are not

adjacent, is less than

2,20mm (0.087in.) but is

greater than, or equal to,

2,00mm (0.079in.) and at

all other locations is

equal to, or greater than,

2,20mm (0.087in.)

Accept

Proceed to step (5), below

(iv) The thickness is between

2,20mm (0.087in.) and

2,00mm (0.079in.) in more

than two locations or in

two adjacent locations

Rework in accordance with SB72-G604

Proceed to step (5), below

(v) Minimum thickness is less

than 2,00mm (0.079in.)

Rework in accordance with SB72-G604

Proceed to step (5), below

(5) Mark the part to record the accomplishment of the NMSB:

(a) Refer to Fig.2.

(b) Refer to Engine Overhaul Processes Manual TSD 594-J, Task

70-00-00-300-363, Marking Methods.

(c) Mark NMSB 72-AG644 adjacent to the part number. Use vibration-peen

equipment.

(6) Record the accomplishment of NMSB 72-AG644 in the engine and module

logbooks.

Printed in Great Britain

RB.211−72−AG644

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Flow Chart description of NMSB 72-AG644

Fig.1 (Sheet 1 of 2)

Printed in Great Britain

RB.211−72−AG644

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Flow Chart description of NMSB 72-AG644

Fig.1 (Sheet 2 of 2)

Printed in Great Britain

RB.211−72−AG644

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LP Turbine Bearing Support and Exhaust Case Assembly - Location of part markings

Fig.2

Printed in Great Britain

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Hub to Conical Panel weld line and flange - measurement areas

Fig.3

Printed in Great Britain

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Measurement locations Y1, Y2, Y3, Y4 and Y5 on the hub to conical panel weld line at

8 circumferential locations

Fig.4

Printed in Great Britain

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Hub to Conical Panel flange Measurement loation X for Hub to Conical Panel flange at

8 circumferential locations

Fig.5

Printed in Great Britain

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Hub to Conical Panel Flange thickness - Sentencing criteria

Fig.6

Printed in Great Britain

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Serial Nos. relating to Modules referenced in 1.,D., Compliance

Fig.7

Printed in Great Britain

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Non-Modification Service Bulletin 72-AG644 Service Data Proforma

See over

APPENDIX 1

Printed in Great Britain

RB.211−72−AG644

Appendix 1 - Page 1 of 2

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Printed in Great Britain

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Appendix 1 - Page 2

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