Visual Inspection of the APU Surge Duct (131-9(A))

TASK 49-51-52-200-002-A
Visual Inspection of the APU Surge Duct (131-9(A))

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

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

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-51-52-000-006-A	Removal of the APU Surge Duct (131-9(A))
TASK 49-51-52-400-004-A	Installation of the APU Surge Duct (131-9(A))
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
APU Surge Duct (131-9(A))

3. Job Set-up
Subtask 49-51-52-860-061-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On the panel 25VU make sure that the APU MASTER SW p/bsw is OFF.
(3) Put the WARNING NOTICE(S) on panel 25VU to tell persons not to start the APU.
(4) Depressurize the aircraft hydraulic systems
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-51-52-865-065-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-51-52-010-058-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 4M (13 FT) in position below the APU access doors 315AL and 316AR.
(2) Open the APU access doors 315AL and 316AR and safety them in the open position (Ref. AMM TASK 52-41-00-010-001).
(3) Set the LIGHT control SW 11LJ to the ON position.
(4) Remove the surge duct (Ref. AMM TASK 49-51-52-000-006).

4. Procedure
Subtask 49-51-52-210-054-A ** ON A/C NOT FOR ALL

A. Inspection of the APU Surge Duct
(1) Examine the surge duct (7) for damage, cracks and discoloration. If the surge duct is defective, replace the surge duct.
(2) Examine the surge duct bracket (8) for damage and cracks.

A 20 days inspection interval should be used as the allowable replacement interval if a duct is found with both legs cracked.
A 70 days inspection interval should be used as the allowable replacement interval if a duct is found with one bracket leg cracked.

5. Close-up
Subtask 49-51-52-410-055-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) Install the surge duct (Ref. AMM TASK 49-51-52-400-004).
(3) Set the LIGHT control SW 11LJ to the OFF position.
(4) Close the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(5) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(6) Remove the access platform(s).

Subtask 49-51-52-865-066-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-51-52-860-062-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:31:19 UTC