Fan Frame Shroud - Local Repair of the Poly-Tetra-Fluoro-Ethylene (PTFE) Varnish in the V-groove [CFML]

TASK 72-24-10-340-801-A
Fan Frame Shroud - Local Repair of the Poly-Tetra-Fluoro-Ethylene (PTFE) Varnish in the V-groove

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

ZONE: 400

1. Reason for the Job
This procedure gives instructions to paint touch-up with PTFE lubricant varnish.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	AIR SOURCE FILTERED, DRY
No specific	AR	BLADE - SHAPED
No specific	1	TAPE - MASKING
No specific	1	THICKNESS MEASURING EQUIPMENT - ULTRASONIC
No specific	1	VISCOMETER
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP1041)	isopropyl alcohol
(Material No.CP2233)	3M-250
(Material No.CP2328)	PTFE varnish
(Material No.CP2721)	CS 333 X
No specific	TA6V

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL, 462AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-803-A	Closing of the Fan Cowl Doors
TASK 72-24-10-210-801-A	Visual Inspection of the Fan Frame Shroud
TASK 78-30-00-040-809-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-809-A	Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
TASK 78-36-00-410-806-A	Closing of the Thrust Reverser Cowl Doors
SPM 706316640007
PTFE Varnish Areas

3. Job Set-up
Subtask 72-24-10-941-051-A

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put WARNING NOTICE(S) in position to tell persons not to operate:

The ENG/MODE selector switch
The ENG/MASTER 1(2) control switch.

(2) On the ENG section of maintenance panel 50VU:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).

Subtask 72-24-10-010-051-A

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(2) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.

Subtask 72-24-10-040-050-A

C. Deactivation of the Thrust Reverser System for Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for maintenance (Ref. AMM TASK 78-30-00-040-809).

Subtask 72-24-10-010-052-A

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR

Subtask 72-24-10-990-050-A

E. Applicable Parts
(1) The subsequent table gives a list of the part numbers that are applicable to this repair.

Table 801 - Applicable Parts

Part Number	Service Bulletin	CSN	Designation
362-907-911-0	-	(15-540, 72-24-00)	Fan frame shroud

4. Procedure

WARNING: REFER TO THE PRODUCT LABEL AND THE MANUFACTURER'S (MATERIAL) SAFETY DATA SHEET (SDS) FOR INSTRUCTIONS ON THE HAZARDS, STORAGE, SAFE HANDLING AND CORRECT USE OF CONSUMABLE PRODUCTS.

WARNING: USE PROTECTIVE GLOVES TO PREVENT INJURY FROM SHARP EDGES AND ROUGH SURFACES.

WARNING: DO NOT LET TITANIUM DUST COLLECT. DISCARD ALL TITANIUM WASTE IN AN APPROVED CONTAINER. TITANIUM DUST IS EXTREMELY FLAMMABLE.

CAUTION: DO NOT USE CHLORINATED SOLVENTS ON TITANIUM PARTS.

CAUTION: WHEN YOU PROCESS TITANIUM PARTS, DO NOT USE TOOL FIXTURE DETAILS MADE OF OR COATED WITH CADMIUM, BISMUTH, TIN, ZINC, GOLD OR SILVER. IF YOU DO, THESE MATERIALS CAN HAVE AN UNWANTED EFFECT ON THE TITANIUM PARTS.

CAUTION: DO NOT USE TOOLS OR CONSUMABLE PRODUCTS THAT WERE USED TO BLEND MATERIALS OTHER THAN TITANIUM, BECAUSE TITANIUM IS EASILY CONTAMINATED.

CAUTION: WHEN YOU USE POWER TOOLS, MAKE SURE THAT YOU DO NOT CAUSE HEAT THAT WILL RESULT IN THERMAL STRESS. THERMAL STRESS CAN CAUSE ENGINE FAILURE.

Subtask 72-24-10-110-050-A

A. Clean the area to be repaired with isopropyl alcohol (Material No.CP1041) .

Subtask 72-24-10-380-050-A

B. Prepare the surface where you will apply the PTFE varnish:

WARNING: DO NOT BREATHE THE PARTICLES WHEN YOU DO THE SANDING. USE PERSONAL PROTECTION EQUIPMENT. USE LOCAL MECHANICAL EXHAUST VENTILATION OR AN APPROVED RESPIRATOR. THE PARTICLES CAN CAUSE INJURY OR IRRITATION TO YOU.

WARNING: DO NOT POINT COMPRESSED GASES AT YOURSELF OR OTHER PERSONS. USE APPLICABLE EYE PROTECTION WHEN YOU USE COMPRESSED GASES. COMPRESSED GASES CAN CAUSE INJURY TO THE EYES.

CAUTION: DO NOT REMOVE OR CHANGE THE SHAPE OR ROUGHNESS OF THE V-GROOVE. DO NOT APPLY A PROCESS WHICH CHANGES THE PARENT MATERIAL PROPERTIES DURING THE REMOVAL OF THE BONDED MATERIAL. IF YOU DO NOT OBEY THESE INSTRUCTIONS, DAMAGE TO THE PART WILL OCCUR.

CAUTION: BE CAREFUL NOT TO TOUCH THE SEAL IN THE V-GROOVE. IF YOU DO, DAMAGE TO THE PART WILL OCCUR.

(1) If necessary, apply mask on the area around the area to be repaired.
(2) Do a light hand-sanding with an CS 333 X (Material No.CP2721) CS grit 333 size from 240 to 600 on the area to be repaired.
(3) If necessary, remove the masking.
(4) Clean the area to be repaired with isopropyl alcohol (Material No.CP1041) .
(5) Dry the area to be repaired with AIR SOURCE FILTERED, DRY.

Subtask 72-24-10-220-050-A

C. Do a visual inspection of the area where you will apply the PTFE varnish (Ref. AMM TASK 72-24-10-210-801).

Subtask 72-24-10-350-050-A

D. Apply the PTFE varnish (Material No.CP2328) , SPM 706316640007, as follows:

PTFE Varnish Areas

(1) Make a test piece of TA6V material or stainless steel per type Z10CNT18 piece along with the part to be varnished for quality assurance.
(2) Prepare the surface of the test piece as follows:
(a) Do a light hand-sanding with an CS 333 X (Material No.CP2721) CS 333 X grit size from 240 to 600 on the area to be repaired.
(b) Clean the area to be repaired with isopropyl alcohol (Material No.CP1041) .
(c) Dry the area to be repaired with AIR SOURCE FILTERED, DRY.
(3) Apply lubricant varnish PTFE minimum 15 minutes after cleaning.
(4) If necessary, apply mask with a TAPE - MASKING around the area to be repaired.
(5) Use a VISCOMETER to get the following viscosity: AFNOR cup (consistometer) No. 4 between 20 seconds and 30 seconds or FORD cup No. 4 between 16 seconds and 26 seconds.
(6) Apply one layer of PTFE varnish and make sure that the thickness is between 0.00028 in. (0.007 mm) and 0.00118 in. (0.030 mm) on the area(s) to be repaired.

NOTE: You can use a measuring equipment THICKNESS MEASURING EQUIPMENT - ULTRASONIC to measure the thickness.

NOTE: An excess of PTFE varnish is permitted on areas A.

(7) If necessary, remove the masking, the overspray or unwanted varnish with isopropyl alcohol (Material No.CP1041) or with a BLADE - SHAPED.
(8) Dry the lubricant varnish PTFE as follows:

At ambient temperature for 48 hours
At a temperature between 131 deg.F (55.00 deg.C) and 149 deg.F (65.00 deg.C) during two hours for a minimum and two hours 30 minutes for a maximum.

Subtask 72-24-10-220-051-A

E. Do a visual examination:
(1) Make sure that the varnished surfaces are smooth, uniform and free from sags, blisters, flakes or foreign material.

NOTE: The coating should be light green.

(2) A smooth transition area between the repaired area and the adjacent areas is required.
(3) Streaks are acceptable if the varnish thickness is in the permitted limits.
(4) If the varnished surfaces fail any of these tests or examinations, remove the coating and reprocess the part.

Subtask 72-24-10-280-050-A

F. Do the following tests:
(1) On the test piece:
(a) Measure the thickness of the varnish (see Para. 4.D.).
(b) Scrape the lubricant varnish using a BLADE - SHAPED. Scrapings must show as a powder.
(c) Criss-cross the area, then apply and press on a strip of 3M-250 (Material No.CP2233) to the test piece following the ISO2409 norm.

NOTE: Lubricant varnish must not peel when the tape is removed.

(2) On the repaired area:
(a) Apply and press on a strip of 3M-250 (Material No.CP2233) on the repaired area.

NOTE: Lubricant varnish shall not peel when the tape is removed.

5. Close-up
Subtask 72-24-10-410-051-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-410-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR

Subtask 72-24-10-440-050-A

B. Do the reactivation of the thrust reverser system after maintenance (Ref. AMM TASK 78-30-00-440-809).

Subtask 72-24-10-410-052-A

C. Close Access
(1) Remove the access platform(s).
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 13:04:10 UTC