Air Leak Test with closed APU Doors

TASK 49-00-00-790-006-A
Air Leak Test with closed APU Doors

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

ZONE: 315
ZONE: 316

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	SAFETY CLIP - CIRCUIT BREAKER

B. Consumable Materials

REFERENCE	DESIGNATION
CP3010	dry developer
(Material No.08CKB9)	Cleaner-Hydraulic Spillage Absorbent powder -
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315	TAIL CONE APU AND ACCESSORY COMPARTMENT
316	TAIL CONE APU AND ACCESSORY COMPARTMENT
315AL, 316AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-00-00-860-008-A	APU Start by External Power
TASK 49-00-00-860-008-A-01	APU Start by Batteries
TASK 49-00-00-860-009-A	APU Shutdown by External Power (131-9(A))
TASK 49-00-00-860-009-A-01	APU Shutdown by Batteries (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
Foil Wrap Installation at Pneumatic System Joints

3. Job Set-up
Subtask 49-00-00-860-105-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On the panel 25VU, make sure that the APU MASTER SW p/bsw is OFF.
(3) Put a warning notice in the cockpit to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-00-00-865-115-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 49-00-00-010-071-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the access platform in position below the APU access doors 315AL and 316AR.
(2) Open the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(3) Set the LIGHT control SW 11LJ to the ON position.

4. Procedure
Subtask 49-00-00-480-056-A ** ON A/C NOT FOR ALL

A. Preparation for the Leak Test
(1) There are two possible procedures to find the location of a pneumatic joint air leak. You can apply CP3010 dry developer or Cleaner-Hydraulic Spillage Absorbent powder - (Material No.08CKB9) and dry around the pneumatic joints. Or you can install aluminum foil around the pneumatic joint location. Use the steps that follow to apply aluminum foil to the pneumatic joint locations:
(a) Wind the foil wrap around the joint one time.
(b) Twist the seam of the foil wrap tight as shown.
(c) Make the foil wrap as tight as possible on the tube but do not rip the wrap.
(d) Attach the foil wrap with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy - at both sides of the pneumatic joint.

Subtask 49-00-00-410-075-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the LIGHT control SW 11LJ to the OFF position.
(3) Close the APU access doors 316AR 315AL and (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).
(5) Remove the WARNING NOTICE(S).

Subtask 49-00-00-865-116-A ** ON A/C NOT FOR ALL

C. 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 49-00-00-790-055-A ** ON A/C NOT FOR ALL

D. Air Leak Test
(1) Start the APU (Ref. AMM TASK 49-00-00-860-008).
(2) During APU operation:

supply bleed air.

(3) Stop the APU (Ref. AMM TASK 49-00-00-860-009).
(4) Put a warning notice in the cockpit to tell persons not to start the APU.

Subtask 49-00-00-865-117-A ** ON A/C NOT FOR ALL

E. 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 49-00-00-010-072-A ** ON A/C NOT FOR ALL

F. Get Access
(1) Put the access platform in position below the APU access doors 315AL and 316AR.
(2) Open the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(3) Set the LIGHT control SW 11LJ to the ON position.

Subtask 49-00-00-080-056-A ** ON A/C NOT FOR ALL

G. Make sure that there no leaks at the joint location, and remove the materials used to check leaks.

5. Close-up
Subtask 49-00-00-410-076-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) Set the LIGHT control SW 11LJ to the OFF position.
(3) Close the APU access doors 316AR 315AL (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).

Subtask 49-00-00-865-118-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 49-00-00-860-106-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 aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 12:43:10 UTC