Repeater Technical Variance

© Rolls-Royce plc (date as shown below).

The information in this document is the property of Rolls-Royce plc and may not be copied, communicated to a third party, or 

used for any purpose other than that which it is supplied without the express written consent of Rolls-Royce plc.

This is a repeat application technical variance. It is the responsibility of the operator / overhaul base to control the application 

of this document. 

This document is supplemental to the Manual(s) specified below and should be suitably stored in accordance with local 

airworthiness requirements.

Declaration of Approval

This document is approved under the authority of Airbus EASA Design Organisation Approval no. EASA.21J.031.

Refer to Repair Design Approval Sheet reference no 

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 1 of Pages 17

Technical Variance No. 132217 Issue 5 Date 23 MAY 2013

Operator / Applicant ALL OPERATORS / 

ALL APPLICANTS

Original Request No. DK_08_03_2013

Engine Type RB211 Engine Mark(s) TRENT 900 ALL ENGINE MARKS

Part Description LP TURBINE EXHAUST CASE (TAIL BEARING HOUSING)

Part No. FW35923, FW51434, FW27718

Manual Title AMM Ref. NA ATA Ref. 72-52-51

TV Title MOUNT LUG FORGING LEADING EDGE INSPECTIONS

Hours NA Cycles NA

Existing Requirement

The Aircraft Maintenance Manual (AMM) does not contain a procedure to inspect the Tail Bearing Housing

(TBH) Mount Lug Forging Leading Edge (LE) area for crack indications on wing

Requested Variance

Currently there is a requirement to inspect the TBH Mount Lug Forging LE area on Trent 900 engines on 

wing. 

NMSB72-AH154 will follow the issue of this repeater TV and will include details of the new inspection. This 

repeater TV includes the details of the inspection until NMSB72-AH154 is finalised and issued. This 

Technical Variance may be applied until 28th June 2013.

The results of this inspection are to be reported to Rolls-Royce.

Summary of Investigation and Conclusions

Rolls-Royce Engineering has reviewed the above requirement and an inspection technique has been developed. This TV is issued to 

instruct the inspection of the TBH Mount Lug Forging LE area. 

Issue 2 of this Repeater Technical Variance is released to update the fly on and re inspection requirements for crack 

indications in the Mount Lug Forging LE area. Additionally, inspection and acceptance criteria for fail safe catcher damage are 

updated for clarity.

Issue 3 is released to correct a formatting error.

Issue 4 is released to correct an error in task reference for removal and installation of the aft exhaust plug.

Issue 5 is released to make the removal and installation of the exhaust nozzle and forward and aft exhaust plugs, optional 

tasks.

Approval on Behalf of Rolls-Royce 
Technical Variance 

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Issue 5

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 2 of Pages 17

A. Manpower Requirements

1) On-wing 

(a) Time to gain access

2.5 hours (2 persons)

(b) Time to inspect Mount Lug Forging LE Areas 

2 hours (2 persons)

(c) Time to restore to serviceable condition

2.5 hours (2 persons)

The FPI defined in this Technical Instruction shall only be performed by personnel qualified to Fluorescent 

Penetrant Inspection FPI Level 2 or higher and in possession of an up to date eyesight record in 

accordance with EN4179/NAS410 or alternative standards/guidelines accepted by the applicable National 

Aviation Authority.

B. Material Price and Availability

OMat 632 – Aerosol penetrant - Commercially Available

OMat 617 – Aerosol developer - Commercially Available

OMat 150 – Acetone - Commercially Available

OMat 2/101 – Lint Free Cloths - Commercially Available

OMat 677 – Penetrant Test Panel - Commercially Available

C. Tooling Price and Availability

Dark Non-Reflective cover to darken the area for inspection – Commercially Available 

UV Light source – Commercially Available

Mirror – Commercially Available

D. References

(1) Aircraft Maintenance Manual (AMM):

(a) 71-13-00, Maintenance Practices, Opening of Fan Cowl Doors

(b) 78-26-00, Maintenance Practices, Opening/Closing of the Fan Exhaust

Cowl or Thrust Reverser

(c) 78-30-00, Deactivation/Reactivation, Make the Thrust Reverser

Unserviceable for Maintenance

(d) 78-11-41-000-801-A Removal of the Exhaust Nozzle

(e) 78-11-42-000-804-A Removal of the Aft Exhaust Plug
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(f) 78-11-42-000-803-A Removal of the Forward Exhaust Plug

(g) 78-11-41-400-801-A Installation of the Exhaust Nozzle

(h) 78-11-42-400-804-A Installation of the Aft Exhaust Plug

(i) 78-11-42-400-803-A Installation of the Forward Exhaust Plug

E. On-Wing –Mount Lug Forging LE Area Inspection

WARNING: YOU MUST BE CAREFUL WHEN YOU WORK ON THE ENGINE AFTER THE 

ENGINE IS SHUTDOWN. THE ENGINE CAN STAY HOT FOR UPTO ONE 

HOUR.

WARNING: YOU MUST NOT TOUCH HOT PARTS WITHOUT APPLICABLE GLOVES. HOT 

PARTS CAN CAUSE INJURY. IF YOU GET AN INJURY, TREAT WITH COLD 

WATER FOR 10 MINUTES, THEN SEEK MEDICAL AID.

1) To get access to the mount lug forging LE Area

(i) Open the Fan Cowl Doors in accordance with AMM Task 71-13-00, Maintenance 

Practices to get access

(ii) Make the Thrust Reverser unserviceable for maintenance in accordance with 

AMM Task 78-30-00 Deactivation/Activation.

WARNING: YOU MUST MAKE THE THRUST REVERSER UNSERVICEABLE (INSTALL 

AND SAFETY THE INHIBITION DEVICE) BEFORE YOU DO WORK ON OR 

AROUND THE THRUST REVERSER. IF YOU DO NOT INSTALL AND SAFETY 

THE INHIBITION DEVICE, THERE IS A RISK THAT THE THRUST REVERSER 

CAN OPERATE ACCIDENTALLY. THIS CAN CAUSE INJURY TO PERSON 

AND/OR DAMAGE TO THE EQUIPMENT.

(iii) Open the Fan Exhaust Cowls in accordance with the AMM, Task 78-26-00

(iv) Remove the Exhaust Nozzle to allow access to the rear of the TBH in 

accordance with AMM, Task 78-11-41-000-801-A

(v) Remove the Aft Exhaust Plug in accordance with AMM, Task 78-11-42-000-804-

A

(vi) Remove the Forward Exhaust Plug in accordance with AMM, Task 78-11-42-

000-803-A

NOTE: STEPS (iv) TO (vi) ARE OPTIONAL TASKS INTENDED TO IMPROVE ACCESS

TO THE TBH. IF SUITABLE ACCESS CAN BE GAINED WITHOUT

PERFORMING SOME OR ALL OF TASKS (iv) TO (vi) THEN THEY ARE NOT

REQUIRED.

(vii) Use appropriate staging and platforms to gain access to the Tail Bearing Housing 

2) Processing the penetrant test panel

(i) The OMat 677 – penetrant test panel must be processed at the beginning of 

each shift and viewed in each engine that is to be inspected during the shift in 

order to ensure that the test environment and materials are acceptable.
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(ii) Ensure the OMat 677 – penetrant test panel is clean and there is no residual 

fluorescence.

(iii) Cover the region of the engine to be inspected with a dark non-reflective cover in 

order to reduce the white light levels in the leading edge inspection area.

(iv) Apply OMat 632 penetrant to the OMat 677 – penetrant test panel by sponge 

applicator or brush. The penetrant must be dispensed from a sealed aerosol can 

and any unused penetrant must go to waste following the inspection.

(v) Leave the penetrant in contact with the panel for 20 minutes.

(vi) After the 20 minutes contact time, take the OMat 677 penetrant test panel inside 

the darkened area to process. Allow 3 minutes for eye adaptation to the low light 

levels.

(vii) Remove the excess penetrant from the panel surface by wiping thoroughly with a 

clean, dry OMat 2/101 – lint free cloth whilst illuminating the panel with UV light.

(viii) Soak a clean OMat 2/10 - lint free cloth in water and then gently squeeze the 

excess water out to reduce the flow of water on the panel surface.

(ix) Whilst illuminating the OMat 677 – penetrant test panel with UV light, wipe off the 

penetrant with the wet cloth before immediately wiping over with a clean, dry 

OMat2/10 lint free cloth. Repeat this process using the minimum application 

necessary to achieve acceptable background fluorescence.

(x) Ensure that the panel is dry by wiping with a clean, dry OMat2/10 lint free cloth.

(xi) Apply a light, even coating of OMat 617 – non-aqueous wet developer from a 

sealed aerosol can to the OMat 677 – penetrant test panel.

(xii) Allow 10 minutes contact time for the developer prior to inspecting the panel.

(xiii) Ensure there are no white light sources or fluorescent items (including clothing) 

within the darkened area.

(xiv) Hold the OMat 677 – penetrant test panel alongside the leading edge of the Top 

Core Vanes and illuminate it with UV light.

(xv) Inspect the OMat 677 – penetrant test panel and check that the visible 

indications match the control photograph for that panel.

(xvi) If the panel matches the photograph then the inspection materials and 

environment are acceptable and the inspections can be performed.

(xvii) Repeat steps (xiii) to (xvi) for each engine to be inspected during the shift. 

Ensure that the inspection area is darkened for each engine.

(xviii) Restore the OMat 677 – penetrant test panel to a completely clean condition and 

ensure there is no residual fluorescence and store in acetone.

3) Carry out the inspection of the Mount Lug Forging LE Area

WARNING: PROTECTIVE GLOVES AND SAFETY GLASSES MUST BE WORN AT ALL 

TIMES DURING THE INSPECTION. IF YOU GET AN INJURY, SEEK MEDICAL 

AID IMMEDIATELY.
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(i) Clean the inspection areas (See Fig. 2) with a clean OMat 2/101 – lint free cloth 

moistened with OMat 150 – acetone. 

(ii) Discard the soiled cloth after use. 

(iii) Repeat the swabbing using fresh OMat 150 – acetone and a fresh OMat 2/101 –

lint free cloth until all deposits have been removed. 

NOTE: THE INSPECTION SURFACE, MUST BE CLEAN, DRY AND FREE FROM 

SOILS, OIL, GREASE, PAINT, COATINGS, CORROSION PRODUCTS, SCALE, 

SMEARED METAL, WELDING FLUX, CHEMICAL RESIDUES OR ANY OTHER 

MATERIAL THAT COULD PREVENT PENETRANT FROM ENTERING A 

DISCONTINUITY, AFFECT PROCESS PERFORMANCE OR PRODUCE AN 

UNACCEPTABLE BACKGROUND.

(iv) Allow 5 minutes for the area to completely dry prior to penetrant application. 

(v) Apply OMat 632 penetrant to the inspection areas in Fig.2. The penetrants must 

be dispensed from a sealed aerosol can and any unused penetrant must go to 

waste. 

(vi) Ensure that the inspection areas are fully covered with penetrant with the aid of 

the UV lamp and mirror. 

(vii) Leave the penetrant in contact with the components for 20 minutes. 

NOTE: THE PENETRANT CONTACT TIME MUST NOT EXCEED 1 HOUR. IF IT DOES 

THE PENETRANT MUST BE REAPPLIED AND 5 MINUTES CONTACT TIME 

ALLOWED.

(viii) After the 20 minutes contact time, remove the excess penetrant from the 

inspection surface by wiping thoroughly with a clean OMat 2/101 – lint free cloth. 

(ix) Soak a clean OMat 2/10 - lint free cloth in water and then gently squeeze the 

excess water out to reduce the flow of water on the component surface. 

(x) Whilst illuminating the inspection area with UV light, wipe off the penetrant with 

the wet cloth before immediately wiping over with a clean, dry OMat2/10 lint free 

cloth. Repeat this process using the minimum application necessary to achieve 

acceptable background fluorescence. 

(xi) Ensure that the inspection area is dry by wiping with a dry OMat2/10 lint free 

cloth. 

(xii) Apply a light, even coating of OMat 617 – non-aqueous wet developer from a 

sealed aerosol can to the inspection area.

(xiii) Allow a minimum of 10 minutes and a maximum of 15 minutes contact time for 

the developer prior to inspection. 

(xiv) Cover the region of the engine with a dark non-reflective cover in order to reduce 

the white light levels. 

(xv) Ensure there are no white light sources or fluorescent items (including clothing) 

within the inspection area. 

(xvi) Positioned inside the darkened area, allow 3 minutes for eye adaptation to the 

low light levels.
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(xvii) Illuminate the inspection surfaces with UV light in the darkened area and view by 

line of sight or by using the mirror as necessary.

(xviii) Assess the Inspection areas for crack indications. White light may be used to aid 

assessment

(xix) The “Wipe Off” technique shall be used to determine the nature of any 

indications. 

1. Dampen a cotton swab with acetone.

2. Wipe once across the indication.

3. Allow the acetone to evaporate and inspect immediately.

4. If the indication reappears then record it as a crack. If the indication does 

not reappear then apply a light, even coating of OMat 617 – nonaqueous wet developer from a sealed aerosol can to the area.

5. Allow the solvent in the developer to evaporate and inspect immediately.

6. If the indication reappears record it as a crack. If the indication does not 

reappear then allow 10 minutes contact time for the developer.

7. If the indication reappears after the 10 minutes contact time then record 

it as a crack. If the indication does not reappear then that area is 

acceptable.

(xx) Record any suspected crack indication in Appendix 1.

Determine whether the indication is continuous or discontinuous where possible.

Measure the length of the indication using a fluorescent comparator gauge.

Photograph any crack indications.

(xxi) No cracks detected ACCEPT

Any discontinuous cracks that total less than 6mm RE-INSPECT 

in length (see Fig.3) WITHIN 75 FC

Any discontinuous cracks that total greater than or RE-INSPECT 

equal to 6mm and less than 9mm in length (see Fig.3) WITHIN 50 FC

Any discontinuous cracks that total greater than or REMOVE ENGINE 

equal to 9mm and less than 12mm in length (see Fig.3) WITHIN 100 FC

 

Any discontinuous cracks that total 12 mm in length REMOVE ENGINE 

or greater (see Fig.3) 

Any single continuous crack less than 2mm in length RE-INSPECT 

(see Fig.4) WITHIN 75 FC

Any single continuous crack greater than or equal RE-INSPECT 

to 2mm and less than 5mm in length (see Fig.4) WITHIN 50 FC

Any single continuous crack greater than or equal REMOVE ENGINE 
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to 5mm and less than 8mm in length (see Fig.4) WITHIN 100 FC

Any single continuous crack equal to or greater than REMOVE ENGINE 

8mm in length (see Fig.4)

(xxii) Once all indications have been evaluated and recorded, remove the penetrant 

processing materials from the inspection surface by wiping with a clean OMat 

2/101 – Lint Free Cloth moistened with OMat 150 – Acetone. 

4) Inspect the fail safe catcher for signs of contact

(i) Visually inspect the LE face of the fail safe catcher (see Fig.5)

NOTE: ON WING VISIBILITY OF THE LE FACE OF THE FAIL SAFE CATCHER IS 

LIMITED. VIEW AS MUCH OF THE LE FACE AS ACCESS ALLOWS AND 

ASSESS FOR DAMAGE SIMILAR TO THAT IN FIG.6. 

NOTE: IF DAMAGE IS FOUND ON FAIL SAFE CATCHER USE BSI EQUIPMENT TO 

MEASURE THE EXTENT OF THE DAMAGE IF REQUIRED.

(ii) If Scored, galled, fretted or dented on the centre lug (fail safe lug) front surface:

 

 (1) Not more than 8,00 mm in width and 1,00 mm in depth ACCEPT

(2) More than 2,60 mm in depth REJECT

(3) More than in (1) and less than in (2) REPAIR,

FRS3253 AMM 

TASK 70-42-

11-300-801-A

within 100

Flight Cycles

(4) If the minimum cross sectional area (Area A, see Fig. 7) REJECT

of the catcher in the repaired areas is less than 1155 sqmm 

after repair.

(iii) Photograph any damage and note location of the damage on the fail safe catcher 

and or the engine mounts. See Fig.6 for example photographs of typical damage. 

 

 5) Measure the distances between the fail safe catcher and the engine mount

(i) When the engine is fully cooled, measure the distances A and B as illustrated in 

Fig. 8.

(ii) Record in Appendix 1.

6) Close access to the TBH

(i) Make sure the work area is clean and clear of tools and other items.

(ii) If applicable, install the Forward Exhaust Plug in accordance with AMM, Task 78-

11-42-400-803-A.

(iii) If applicable, install the Aft Exhaust Plug in accordance with AMM, Task 78-11-

42-400-804-A.
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(iv) If applicable, install the Exhaust Nozzle in accordance with AMM, Task 78-11-41-

400-801-A.

(v) Close the Fan Exhaust Cowls in accordance with AMM 78-26-00, Maintenance 

Practices.

(vi) Make the Thrust Reverser serviceable after maintenance in accordance with 

AMM 78-30-00, Deactivation/Activation as necessary.

(vii) Close the Fan Cowl Doors in accordance with AMM Task 71-13-00, Maintenance 

Practices.
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Figure 1 – Tail Bearing Housing
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Figure 2 - Mount Lug Forging LE Area

VIEW LOOKING AFT
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Figure 3 – Discontinuous crack indication
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Figure 4 - Continuous crack indication
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Figure 5 - Fail Safe Catcher Inspection locations

FWD

FWD

View looking 

FWD
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Figure 6 - On Wing - Fail Safe Catcher Damage
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Figure 7 - Repair Acceptance Criteria
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Figure 8 – Distances between fail safe catcher and engine mount

FWD

A B
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APPENDIX 1

This form (or similar) to be completed for every engine/component inspected

Results to be sent to Rolls-Royce via your Service Representative

Feedback Sheet TV 132217

Aircraft and Engine Position

Operator

Date of Inspection

Engine Serial Number

Engine Hours Since New

Engine Cycles Since New

08 Module Serial Number

08 Module Hours Since New

08 Module Cycles Since New

Component Part Number

Component Serial Number

Component Hours Since 

New

Component Cycles Since 

New

Inspection result and comments

On Wing Inspection of 

Mount Lug Forging 

Leading Edge Area

Any crack indications?

Max continuous length

Max discontinuous length

Photographs of crack 

indications

On Wing inspection of 

Fail Safe Catcher LE 

face and any 

photographs of damage 

Distance A between Fail 

Safe Catcher LE and 

Engine mount (mm)

Distance B between Fail 

Safe Catcher TE and 

Engine mount (mm)