Deactivation of the APU Leak-Detection Loop

TASK 36-12-00-040-810-A
Deactivation of the APU Leak-Detection Loop

WARNING: MAKE SURE THAT THE PNEUMATIC SYSTEM IS DEPRESSURIZED BEFORE YOU START WORK. PRESSURIZED AIR CAN CAUSE INJURY TO PERSONNEL.

ZONE: 191
ZONE: 211

1. Reason for the Job
MMEL 36-09-01B
AIR APU BLEED LEAK ALERT
MMEL 36-09-01C
AIR APU BLEED LEAK ALERT
MMEL 36-09-01D
AIR APU BLEED LEAK ALERT
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
191	AIR CONDITIONING COMPT AND FAIRINGS
211	COCKPIT
191DB

C. 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 36-11-00-740-001-A	BITE Test of the BMC 1(2)
TASK 36-22-00-790-001-A	Leak Check on all the Bleed Air Ducts and the Packs Components
AWM 362201

3. Job Set-up
Subtask 36-12-00-861-060-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 36-12-00-941-085-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) In the cockpit, on AIR COND panel 25VU:
(a) Make sure that the ENG BLEED 1 and 2 pushbutton switches are released (the OFF legends are on).
(b) Make sure that the APU BLEED pushbutton switch is released (the ON legend is off).
(c) Make sure that the PACK 1 and 2 pushbutton switches are released (the OFF legends are on).
(d) Make sure that the X BLEED selector switch is set to the OFF position.
(e) Put a WARNING NOTICE(S) in position to tell persons not to operate the ENG BLEED 1 and 2 pushbutton switches.
(f) Put the WARNING NOTICE(S) in position to tell persons not to operate the APU BLEED system.
(2) Open access door 191DB on the HP ground connector:
(a) Put the WARNING NOTICE(S) in position to tell persons not to pressurize the pneumatic system.

4. Procedure
Subtask 36-12-00-740-055-A ** ON A/C NOT FOR ALL

A. BITE Test
(1) Do the BITE test of BMC 1(2) (Ref. AMM TASK 36-11-00-740-001):
(a) Make sure that the fault "36-22-17 - APU LOOP" comes into view.

Subtask 36-12-00-790-074-A ** ON A/C NOT FOR ALL

B. Leak Test
(1) Do a leak check of the APU bleed-air ducts (Ref. AMM TASK 36-22-00-790-001):
(a) Make sure that there are no leaks.

NOTE: A leak on the APU bleed-air ducts is a NO GO condition.

Subtask 36-12-00-865-171-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR BLEED/X FEED/VALVE/BAT	2HV	D13
49VU	AIR BLEED/ENG 1/CTL	3HA1	D12
49VU	AIR BLEED/ENG 1/MONG	2HA1	D11
122VU	AIR BLEED/ENG 2/CTL	3HA2	Z23
122VU	AIR BLEED/ENG 2/MONG	2HA2	Z22
122VU	AIR BLEED/X FEED VALVE/NORM	1HV	Z20

Subtask 36-12-00-040-061-A ** ON A/C NOT FOR ALL

D. Deactivation of the APU Leak-Detection Loop
(1) On lower-right connector-plate 95VU, do the steps that follow:
(a) Remove connector 251VC-A from its location.
(b) Disconnect pins 25 and 26 from connector 251VC-A and put the CAP - BLANKING on the pins to prevent them from contamination AWM 362201.
(c) Identify the disconnected cables with a label.
(d) Install connector 251VC-A on the plate.

Subtask 36-12-00-865-172-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
49VU	AIR BLEED/X FEED/VALVE/BAT	2HV	D13
49VU	AIR BLEED/ENG 1/CTL	3HA1	D12
49VU	AIR BLEED/ENG 1/MONG	2HA1	D11
122VU	AIR BLEED/ENG 2/CTL	3HA2	Z23
122VU	AIR BLEED/ENG 2/MONG	2HA2	Z22
122VU	AIR BLEED/X FEED VALVE/NORM	1HV	Z20

5. Close-up
Subtask 36-12-00-860-156-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).
(3) Close access door 191DB.
(4) Make an entry in the logbook.

Subtask 36-12-00-862-057-A ** ON A/C NOT FOR ALL

B. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 01:14:52 UTC