Repair Damaged or Missing Helicoil Insert(s) in the High Pressure Compressor (HPC), Front Case Assembly, by Replacement (Front Case Only) - VRS 6521 [IAE]

TASK 72-41-31-300-010-B
Repair Damaged or Missing Helicoil Insert(s) in the High Pressure Compressor (HPC), Front Case Assembly, by Replacement (Front Case Only) - VRS 6521

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

ZONE: 453
ZONE: 454
ZONE: 463
ZONE: 464

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	1	DRILL - HAND
No specific	AR	PENETRANT TEST EQUIPMENT
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
453	HOT SECTION
454	HOT SECTION
463	HOT SECTION
464	HOT SECTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 70-23-05-230-010-A	Local Application of Fluorescent Penetrant Inspection
TASK 70-35-08-300-010-A	Install and Repair Wire Thread Inserts
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-13-00-410-010-A	Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 72-00-00-200-016-B	Inspection of the HP Compressor
TASK 72-00-00-200-016-B-01	Inspection of the HP Compressor
TASK 78-30-00-040-012-A	Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance
TASK 78-30-00-440-012-A	Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after Ground Maintenance
TASK 78-32-00-010-010-A	Opening of the Thrust Reverser Halves
TASK 78-32-00-410-010-A	Closing of the Thrust Reverser Halves
Repair Details and Dimensions

3. Job Set-up
Subtask 72-41-31-941-053-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Put a WARNING NOTICE(S) in position to tell persons not to start the engine.
(2) Make sure that the engine shutdown occurred five minutes or more before you do this procedure.
(3) On overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/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 72-41-31-010-052-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(4) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.

Subtask 72-41-31-040-051-A ** ON A/C NOT FOR ALL

C. Deactivate the thrust reverser (Ref. AMM TASK 78-30-00-040-012).

Subtask 72-41-31-010-053-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser halves (Ref. AMM TASK 78-32-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR

4. Procedure
Subtask 72-41-31-220-054-A ** ON A/C NOT FOR ALL

A. Examination of the Securing Screw(s) of the Borescope Port Cover
(1) If the screw head(s) is (are) damaged, do Step B.
(2) If the screw head(s) is (are) not damaged (Ref. AMM TASK 72-00-00-200-016).

Subtask 72-41-31-350-054-A ** ON A/C NOT FOR ALL

B. Removal of the Damaged Securing Screw(s) of the Borescope Port Cover

CAUTION: YOU MUST TAKE CARE, WHEN YOU DRILL OUT DAMAGED SCREW(S), NOT TO DAMAGE THE HELICOIL INSERT OR H.P.COMPRESSOR FRONT CASE ASSEMBLY. KEEP THE DRILL IN THE SAME CENTER AS THE DAMAGED SCREW(S).

(1) Drill through the screw head(s) with a 0.118 in. (3.00 mm) to 0.157 in. (3.99 mm), diameter drill, to a depth of 0.625 in. (15.87 mm). Use a DRILL - HAND, and make sure that you keep the drill in the same center as the damaged screw(s).
(2) Remove the remaining screw(s) with standard easy cut tools. Blow out all swarf with a clean dry air blast.
(3) Clean out the tapped hole with a 0.250-28 UNJF-3A plug tap. Make sure that the threads are free running.

Subtask 72-41-31-220-055-A ** ON A/C NOT FOR ALL

C. Examination of the helicoil insert(s) (Ref. AMM TASK 70-35-08-300-010).
(1) If the helicoil insert(s) is (are) damaged, do Step D.
(2) If the helicoil insert(s) is (are) not damaged (Ref. AMM TASK 72-00-00-200-016).

Subtask 72-41-31-350-055-A ** ON A/C NOT FOR ALL

D. Repair of the Damaged Helicoil Insert(s)
(1) Remove the damaged helicoil insert(s) (Ref. AMM TASK 70-35-08-300-010).
(a) Use standard workshop equipment.

Subtask 72-41-31-350-056-A ** ON A/C NOT FOR ALL

E. Installation of the Helicoil Insert(s)
(1) Install the helicoil insert(s) (Ref. AMM TASK 70-35-08-300-010).
(a) Use AGS3732 insert, 01-432 (2 off) or AGS3733 insert, 01-432 (2 off) as necessary and standard workshop equipment.

Subtask 72-41-31-230-051-A ** ON A/C NOT FOR ALL

F. Penetrant Crack Test
(1) Do a local penetrant crack test on the repaired area(s) (Ref. AMM TASK 70-23-05-230-010).
(a) Cracks are not permitted. Use PENETRANT TEST EQUIPMENT.

Subtask 72-41-31-220-056-A ** ON A/C NOT FOR ALL

G. Examination of the Helicoil Insert(s)
(1) Examine the helicoil insert(s) (Ref. AMM TASK 70-35-08-300-010).
(2) Make sure that the insert is installed 0.75 to 1.50 thread pitch below the surface.
(3) Use workshop inspection equipment.

Subtask 72-41-31-350-057-A ** ON A/C NOT FOR ALL

H. Do an entry in the logbook, if replacement helicoil insert(s) is (are) installed.

5. Close-up
Subtask 72-41-31-410-052-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser halves (Ref. AMM TASK 78-32-00-410-010):
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 72-41-31-440-051-A ** ON A/C NOT FOR ALL

B. Do the reactivation of the thrust reverser (Ref. AMM TASK 78-30-00-440-012).

Subtask 72-41-31-410-053-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls (Ref. AMM TASK 71-13-00-410-010):
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(4) Remove the access platform(s).
(5) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 13:00:52 UTC