Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly [PW11]

TASK 72-41-01-300-801-A
Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly

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 chase the damaged igniter boss threads on the outer diffuser case assembly.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	VACUUM CLEANER
PWA26657	1	TAP CHASING DIFFUSER CASE SPARK IGNITER THREAD

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 70-27-00-910-804-A	SPOP 208 - Degreasing of Parts by Solvent Wiping
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 72-41-01-920-803-A	Replacement of the Diffuser Case Insert and Spacer
TASK 74-21-01-400-801-A	Installation of the Igniter Plug
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
Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly

3. Job Set-up
Subtask 72-41-01-941-054-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)

Subtask 72-41-01-010-058-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.

Subtask 72-41-01-040-054-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 72-41-01-010-059-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
Subtask 72-41-01-350-050-A ** ON A/C NOT FOR ALL

A. Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly

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

(1) Find the two igniter bosses on the outer diffuser case.

Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly ** ON A/C NOT FOR ALL

(2) Chase the igniter boss threads with a PWA26657 TAP CHASING DIFFUSER CASE SPARK IGNITER THREAD fully through.

Repair of the Igniter Boss Chase Thread on the Outer Diffuser Case Assembly ** ON A/C NOT FOR ALL

NOTE: You can repair minor thread damage with a thread chase procedure. If you do a thread chase, you must use a VACUUM CLEANER to keep debris out of the engine. If you cannot repair the threads by thread chase, you cannot repair the part by this procedure.

(3) Clean the repair area(s) by SPOP 208 (Ref. AMM TASK 70-27-00-910-804).
(4) Do an inspection of the chased threads with a go/no go gage. If the results are unsatisfactory, you cannot repair the part by this procedure. Missing, stripped, cracked, or damaged threads are not permitted.
(5) Install the igniter plug insert(s) (Ref. AMM TASK 72-41-01-920-803).
(6) Install the igniter plugs (Ref. AMM TASK 74-21-01-400-801).
(7) Examine the assembly for foreign objects, damage, and correct assembly.

5. Close-up
Subtask 72-41-01-410-058-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 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 72-41-01-440-054-A ** ON A/C NOT FOR ALL

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

Subtask 72-41-01-410-059-A ** ON A/C NOT FOR ALL

C. 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 WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:49:34 UTC