Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 2 of 10 Pages

Manpower Requirements

1) On-wing 

Time to gain access

0.5 hour (1 person)

Time to inspect Tail Bearing Housing (TBH) Mount Lug Run-outs

2 hours (2 persons)

Time to restore to serviceable condition

0.5 hour (1 person)

2) In Shop

Time to inspect Tail Bearing Housing (TBH) Mount Lug Run-outs

2 hours (2 persons)

The Fluorescent Penetrant Inspection (FPI) defined in this Technical Instruction shall only be 

performed by personnel qualified to 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.

Materials 

OMat 651F - F2B - AMS2644 Type 1, Method D, Level 3 (1D3) compliant aerosol 

penetrant (Fluorescent, Post-Emulsified, Medium Sensitivity).

OMat 617 – AMS2644 Form d – Non-Aqueous Wet Developer – Aerosol.

Ultra Violet Light Source capable of providing a minimum UV radiation intensity of 

1200 μW/cm2 at the inspection surface.

Dark Non-Reflective cover to darken the area for inspection.

OMat 150 – Acetone.

OMat 2/101 – Lint Free Cloths.

OMat 677 – Penetrant Test Panel.

Visual Aids as per AMM Task 70-20-02, Fluorescent Penetrant Inspection.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 3 of 10 Pages

PROCEDURE – ON WING

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 Tail Bearing Housing (TBH) Mount Lug Run-outs

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. Use appropriate staging to gain access to the Tail Bearing Housing TBH

2) Carry out the inspection on the Mount Lug Run-outs

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

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

AID IMMEDIATELY.

i. This inspection must be performed in accordance with the requirements of AMM

70-20-02, Fluorescent Penetrant Inspection.

ii. Local cleaning of the inspection areas must be completed prior to FPI.

iii. Apply OMat 150 – Acetone to a clean OMat 2/101 – Lint Free Cloth.

iv. Clean the inspection surfaces (see Figures 1 and 2) with the moistened 

cloth.

v. Ensure that all contaminants have been removed. If necessary repeat 

steps (iii) and (iv) in order to achieve this.

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.

vi. Allow 10 minutes for the area to completely dry prior to penetrant 

application.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 4 of 10 Pages

vii. Penetrant Application - Apply OMat 651F – 1D3 Penetrant to the inspection 

areas (Figures 1 and 2) by brush or sponge applicator. The penetrant must be 

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

waste.

viii. Ensure that the inspection area is fully covered with penetrant with the aid of a 

UV lamp.

ix. Apply OMat 651F – 1D3 Penetrant to the OMat 677 – Penetrant Test Panel.

x. Leave the penetrant in contact with the components for 30 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.

xi. Penetrant Removal - After the 30 minutes contact time, remove the excess 

penetrant from the inspection surface and the OMat 677 – Penetrant Test Panel 

by wiping thoroughly with a clean OMat 2/101 – Lint Free Cloth.

xii. Whilst illuminating with UV light, wipe off the penetrant with a clean 

OMat 2/10 - Lint Free Cloth moistened with OMat 150 – Acetone. Use the 

minimum application necessary to achieve acceptable background fluorescence 

and ensure than acetone is not allowed to flow on the inspection surface.

xiii. Ensure that all traces of the OMat 150 – Acetone have been completely 

removed.

xiv. Develop - Apply a light, even coating of OMat 617 – Non-Aqueous Wet 

Developer from a sealed aerosol can to the inspection area and the OMat 677 –

Penetrant Test Panel.

xv. Allow 10 minutes contact time for the developer.

xvi. Cover the region of the engine with a dark non-reflective cover in order to reduce 

the white light levels.

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

within the inspection area or the inspector’s field of vision.

xviii. Do not wear darkened or light sensitive glasses.

xix. Allow 1 minute for eye adaptation to the darkened area.

xx. Illuminate the OMat 677 – Penetrant Test Panel with UV light at an intensity of no 

less than 1200 μW/cm2 in the darkened area.

xxi. Inspect the OMat 677 – Penetrant Test Panel and check that the 4 largest 

indications are visible and match the control photograph for that individual panel.

xxii. Illuminate the inspection surface with UV light at an intensity of no less than 

1200 μW/cm2 in the darkened area.

xxiii. Inspect the Mount Lug Run-Outs for crack indications.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 5 of 10 Pages

xxiv. The “Wipe Off” technique can be used to aid the evaluation of any indications 

and must be performed as directed by AMM 70-20-02, 

Fluorescent Penetrant Inspection.

xxv. The cause of all indications must be evaluated under white light using visual aids, 

such as magnification, as appropriate.

xxvi. Record any suspected crack indication in Appendix x. Report any suspected 

crack indications to Rolls-Royce local representative.

xxvii. Post Clean - 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.

3) Close access to the Tail Bearing Housing (TBH)

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

ii.Close the Fan Exhaust Cowls in accordance with AMM 78-26-00, 

Maintenance Practices.

iii.Make the Thrust Reverser serviceable after maintenance in accordance 

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

iv.Close the Fan Cowl Doors in accordance with AMM Task 71-13-00, 

Maintenance Practices.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 6 of 10 Pages

PROCEDURE – IN SHOP

1) Carry out the inspection on the Mount Lug Run-outs

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

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

AID IMMEDIATELY.

i. This inspection must be performed in accordance with the requirements of

70-00-00, Overhaul Process 210, Fluorescent Penetrant Inspection.

ii. Local cleaning of the inspection areas must be completed prior to FPI.

iii. Apply OMat 150 – Acetone to a clean OMat 2/101 – Lint Free Cloth.

iv. Clean the inspection surfaces (see Figures 1 and 2) with the moistened 

cloth.

v. Ensure that all contaminants have been removed. If necessary repeat 

steps (iii) and (iv) in order to achieve this.

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.

vi. Allow 10 minutes for the area to completely dry prior to penetrant 

application.

vii. Penetrant Application - Apply OMat 651F – 1D3 Penetrant to the inspection 

areas (Figures 1 and 2) by brush or sponge applicator. The penetrant must be 

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

waste.

viii. Ensure that the inspection area is fully covered with penetrant with the aid of a 

UV lamp.

ix. Apply OMat 651F – 1D3 Penetrant to the OMat 677 – Penetrant Test Panel.

x. Leave the penetrant in contact with the components for 30 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.

xi. Penetrant Removal - After the 30 minutes contact time, remove the excess 

penetrant from the inspection surface and the OMat 677 – Penetrant Test Panel 

by wiping thoroughly with a clean OMat 2/101 – Lint Free Cloth.

xii. Whilst illuminating with UV light, wipe off the penetrant with a clean 

OMat 2/10 - Lint Free Cloth moistened with OMat 150 – Acetone. Use the 

minimum application necessary to achieve acceptable background fluorescence 

and ensure than acetone is not allowed to flow on the inspection surface.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 7 of 10 Pages

xiii. Ensure that all traces of the OMat 150 – Acetone have been completely 

removed.

xiv. Develop - Apply a light, even coating of OMat 617 – Non-Aqueous Wet 

Developer from a sealed aerosol can to the inspection area and the OMat 677 –

Penetrant Test Panel.

xv. Allow 10 minutes contact time for the developer.

xvi. Cover the region of the engine with a dark non-reflective cover in order to reduce 

the white light levels.

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

within the inspection area or the inspector’s field of vision.

xviii. Do not wear darkened or light sensitive glasses.

xix. Allow 1 minute for eye adaptation to the darkened area.

xx. Illuminate the OMat 677 – Penetrant Test Panel with UV light at an intensity of no 

less than 1200 μW/cm2 in the darkened area.

xxi. Inspect the OMat 677 – Penetrant Test Panel and check that the 4 largest 

indications are visible and match the control photograph for that individual panel.

xxii. Illuminate the inspection surface with UV light at an intensity of no less than 

1200 μW/cm2 in the darkened area.

xxiii. Inspect the Mount Lug Run-Outs for crack indications.

xxiv. The “Wipe Off” technique can be used to aid the evaluation of any indications 

and must be performed as directed by 70-00-00, Overhaul Process 210,

Fluorescent Penetrant Inspection.

xxv. The cause of all indications must be evaluated under white light using visual aids, 

such as magnification, as appropriate.

xxvi. Record any suspected crack indication in Appendix 3. Report any suspected 

crack indications to Rolls-Royce local representative.

xxvii. Post Clean - 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.
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 8 of 10 Pages

Figure 1 - Mount Lug Run Outs

Figure 2 - Inspection Areas

Inspection Areas:

The curved faces in 

these 2 positions on 

each side of the 

engine must be 

inspected. In 

addition, 

approximately 

5 mm coverage is 

required around the 

corners. 250 mm
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 9 of 10 Pages

APPENDIX 1

Trent 900 Engines to be inspected ON WING using this procedure

Engine Number

91035

91039

91048

APPENDIX 2

Trent 900 Engines to be inspected IN SHOP using this procedure

Engine Number

91047
Technical Variance 

Continuation Sheet

TV No. 

124801

Issue 2

Rolls-Royce plc. Proprietary Information – Not for Manufacture 

Page 10 of 10 Pages

APPENDIX 3

This form to be completed for every engine/component inspected

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

Feedback Sheet TV124801

Overhaul Base (if applicable)

Operator

Engine Mark

Date of Inspection

Engine Serial Number

Engine Hours Since New

Engine 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 Runouts 

(if applicable) 

In Shop Inspection of 

Mount Lug Run-outs 

(if applicable)