Detailed Visual Inspection (DVI) of the Fan Case Rear Acoustic Liner Segment [PW11]

TASK 72-21-01-220-801-A
Detailed Visual Inspection (DVI) of the Fan Case Rear Acoustic Liner Segment

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
Use this procedure to do a Detailed Visual Inspection (DVI) of the fan case rear acoustic liner segments.
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	1	MAT - PROTECTIVE
636-1100-3GSE	1	INLET COWL PROTECT COVER

B. Work Zones and Access Panels

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

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-802-A	Closing of the Fan Cowl Doors
TASK 72-21-01-320-803-A	Repair the Fan Case Rear Acoustic Liner
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-30-00-440-805-A	Reactivation of the Thrust Reverser System after Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
TASK 78-36-00-410-802-A	Closing of the Thrust Reverser Cowl-Doors
Fan Case Rear Acoustic Liner Segments

3. Job Set-up
Subtask 72-21-01-941-051-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833)
(2) Put an 636-1100-3GSE INLET COWL PROTECT COVER or equivalent MAT - PROTECTIVE inside the engine inlet cowl and on the inside surfaces of the fan case.

Subtask 72-21-01-010-066-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR
(2) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.

Subtask 72-21-01-040-053-A ** ON A/C NOT FOR ALL

C. Deactivation of the Thrust Reverser 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 78-30-00-040-805).

Subtask 72-21-01-010-067-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL 462AR

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 72-21-01-220-050-A ** ON A/C NOT FOR ALL

A. Detailed Visual Inspection of the Fan Case Rear Acoustic Liner Segment
(1) Put an 636-1100-3GSE INLET COWL PROTECT COVER or equivalent MAT - PROTECTIVE inside the engine inlet cowl and on the inside surfaces of the fan case.
(2) Do a detailed visual inspection of the rear fan case acoustic liner segments. See Table 1.

NOTE: The limits given in Table 1 are calculated to make sure that the liner segments are structurally acceptable. Liners that have many repairs can increase engine noise.

(3) In areas where you can see object damage on the liners, do as follows:
(a) Use a small piece of metal, such as a coin, to tap the area where there is damage and then tap the adjacent area.
(b) If there is a difference in the sound, there is disbond.

Table 1 - DVI of the Rear Acoustic Liner Segment

EXAMINE	DAMAGE	DISPOSITION
For dents	Any amount with smooth, round bottoms that do not break the bond between the honeycomb material and the perforated liner.	Permitted for continued service.
	Any amount to the fan case wall.	Not permitted. Remove the engine before the next flight.
For nicks, gouges or scratches	Any amount provided honeycomb is not exposed and does not break the bond between the honeycomb material and the perforated liner.	Permitted for continued service.
	Any amount to the fan case wall.	Not permitted. Remove the engine before the next flight.
For cracks, punctures or tears	Any number of cracks in the perforated liner, of any length, provided the crack does not form a loop, there is no disbond and no liner material is missing.	Permitted for continued service.
	Any looped cracks, punctures or tears in the perforated liner up to 6 in.2 (3871 mm2) total area and that do not break the bond between the fan case and the honeycomb material.	Not permitted. Cut any materials that extends into the airstream before the next flight and repair the acoustic liner or remove the engine in 50 flight hours (Ref. AMM TASK 72-21-01-320-803).
	Any looped cracks, punctures or tears in the perforated liner over 6 in.2 (3871 mm2) total area or that break the bond between the fan case and the honeycomb material.	Not Permitted. Remove the engine before the next flight.
	Any amount to the fan case wall.	Not Permitted. Remove the engine before the next flight.
NOTE: If the damaged area includes a non-repairable area, do not perform the repair and remove the engine before the next flight. Fan Case Rear Acoustic Liner Segments ** ON A/C NOT FOR ALL
For broken adhesive bond	Between the honeycomb material and the perforated liner.
	Up to three locations, 2 in.2 (1290.32 mm2) maximum for each location and 5 in. (127.00 mm) minimum from the adjacent damage area, where the perforated liner does not extend into the air stream and where the broken adhesive bond does not extend to the edge of the liner.	Permitted for continued service.
	If exposed, visually examine for disbond between the fan case wall and the honeycomb material.
	Any amount.	Not permitted. Remove the engine before the next flight.
	Any other broken adhesive bond conditions.	Not permitted. Remove the engine before the next flight.
NOTE: Do a tap test to find areas of bad (broken) bond.
For delamination	Any amount.	Not Permitted. Remove the engine before the next flight.

(4) Remove the MAT - PROTECTIVE from the inside of the air intake cowl.
(5) Examine the assembly for foreign objects, damage, and correct assembly.

5. Close-up
Subtask 72-21-01-860-051-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).

Subtask 72-21-01-410-063-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Close the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL 462AR

Subtask 72-21-01-440-053-A ** ON A/C NOT FOR ALL

C. Do the reactivation of the thrust reverser system after maintenance (Ref. AMM TASK 78-30-00-440-805).

Subtask 72-21-01-410-064-A ** ON A/C NOT FOR ALL

D. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR
(2) Remove the access platform(s).

[Rev.10 from 2021] 2026.04.01 02:48:22 UTC