W DOC AIRBUS | AMM A320F

Check Firing Circuit Continuity

TASK 26-22-00-720-001-A
Check Firing Circuit Continuity

WARNING: BE VERY CAREFUL WHEN YOU MOVE A FULL FIRE EXTINGUISHER BOTTLE. A SUDDEN OR HEAVY SHOCK TO A FULL BOTTLE CAN CAUSE UNWANTED DISCHARGE AND INJURY TO PERSONS.
WARNING: CAREFULLY OBEY THE APPROVED PROCEDURE FOR THIS TASK. TO PREVENT THE EXPLOSION OF THE CARTRIDGE, MAKE SURE THAT YOU INSTALL AN ELECTROSTATIC PROTECTIVE CAP ON THE DISCHARGE CARTRIDGE WHEN YOU DO THIS TASK.
ZONE: 210
1. Reason for the Job
Refer to the MPD TASK: 262200-03
CHECK FIRING CIRCUIT CONTINUITY
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
1
ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific
1
FLASHLIGHT
No specific
AR
SAFETY CLIP - CIRCUIT BREAKER
No specific
1
VOLTMETER - DC
6971-0010
1
CAP SHUNT-FIRE BOTTLE
MS25043-10DA
1
CARTRIDGE CAP
 B. Work Zones and Access Panels
ZONE/ACCESS
ZONE DESCRIPTION
210
CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
314AR
 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-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-02
De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 26-22-00-710-001-A
Operational Test of the APU Fire-Extinguishing Loop/Squib
TASK 52-41-23-010-801-A
Opening of Access Door 314AR
TASK 52-41-23-410-801-A
Closing of Access Door 314AR
F APU Fire-Extinguisher Bottle
3. Job Set-up
Subtask 26-22-00-861-056-A
A. Aircraft Maintenance Configuration
   (1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002) or (Ref. AMM TASK 24-41-00-861-002).
Subtask 26-22-00-865-060-A
B. Open, safety and tag this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUAPU/APU/CTL2KDL42
121VUAPU/ECB/SPLY1KDL41
121VUAPU/FIRE/EXTIG/SQUIB/B2WFL39
121VUAPU/FIRE/EXTIG/SQUIB/A1WFL38
Subtask 26-22-00-010-052-A ** ON A/C NOT FOR ALL
C. Get Access
F APU Fire-Extinguisher Bottle ** ON A/C NOT FOR ALL
WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.
   (1) Put on and attach a safety harness before you start work in the work area
   (2) Put an ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below access door 314AR.
   (3) Open access door 314AR and safety it in the open position.
(Ref. AMM TASK 52-41-23-010-801).
   (4) If necessary, use a FLASHLIGHT.
   (5) Disconnect electrical connector 12WF-A (2) from cartridge 12WF (1).
   (6) Put a MS25043-10DA CARTRIDGE CAP (3) on cartridge 12WF (1).
Subtask 26-22-00-010-052-B ** ON A/C NOT FOR ALL
C. Get Access
F APU Fire-Extinguisher Bottle ** ON A/C NOT FOR ALL
WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.
   (1) Put on and attach a safety harness before you start work in the work area
   (2) Put an ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in posotion below access door 314AR.
   (3) Open access door 314AR and safety it in the open position.
(Ref. AMM TASK 52-41-23-010-801).
   (4) If necessary, use a FLASHLIGHT.
   (5) Disconnect electrical connector 12WF-A (2) from cartridge 12WF (1).
   (6) Put a 6971-0010 CAP SHUNT-FIRE BOTTLE (3) on cartridge 12WF (1).
Subtask 26-22-00-865-120-A
D. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUAPU/FIRE/EXTIG/SQUIB/B2WFL39
121VUAPU/FIRE/EXTIG/SQUIB/A1WFL38
4. Procedure
Subtask 26-22-00-720-050-A
A. Test
ACTION
RESULT
1.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin A and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads zero.
2.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin B and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads zero.
3.On APU FIRE panel 20VU:
  • Lift the guard and push the APU FIRE pushbutton switch.
On APU FIRE panel 20VU:
  • The SQUIB legend in the AGENT pushbutton switch comes on.
4.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin A and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads zero.
5.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin B and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads zero.
6.On APU FIRE panel 20VU:
  • Push and hold the AGENT pushbutton switch.
On APU FIRE panel 20VU:
  • The SQUIB legend in the AGENT pushbutton switch stays on.
7.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin A and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads a value between 26.5V and 29V.
8.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin B and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads a value between 26.5V and 29V.
9.On APU FIRE panel 20VU:
  • Release the AGENT pushbutton switch.
On APU FIRE panel 20VU:
  • The SQUIB legend in the AGENT pushbutton switch stays on.
10.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin A and the ground.
At electrical connector 12WF-A (2)
  • The VOLTMETER - DC reads zero.
11.At electrical connector 12WF-A (2):
  • Connect the VOLTMETER - DC to pin B and the ground.
At electrical connector 12WF-A (2):
  • The VOLTMETER - DC reads zero.
12.On APU FIRE panel 20VU:
  • Push the APU FIRE pushbutton switch.
On APU FIRE panel 20VU:
  • The SQUIB legend in the AGENT pushbutton switch goes off.
  • Put the guard of the APU FIRE pushbutton switch in the correct position.
Make sure that the APU FIRE pushbutton switch is in its latched position before you close the guard.
5. Close-up
Subtask 26-22-00-865-121-A
A. Open, safety and tag this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUAPU/FIRE/EXTIG/SQUIB/B2WFL39
121VUAPU/FIRE/EXTIG/SQUIB/A1WFL38
Subtask 26-22-00-410-053-A ** ON A/C NOT FOR ALL
B. Close Access
   (1) Remove the MS25043-10DA CARTRIDGE CAP (3) from cartridge 12WF (1).
   (2) Make sure that all the electrical connections are clean and in the correct condition.
   (3) Connect electrical connector 12WF-A (2) to cartridge 12WF (1).
   (4) Make sure that the work area is clean and clear of tools and other items.
   (5) Close access door 314AR (Ref. AMM TASK 52-41-23-410-801).
   (6) Remove the access platform(s).
Subtask 26-22-00-410-053-B ** ON A/C NOT FOR ALL
B. Close Access
   (1) Remove the 6971-0010 CAP SHUNT-FIRE BOTTLE (3) from cartridge 12WF (1).
   (2) Make sure that all the electrical connections are clean and in the correct condition.
   (3) Connect electrical connector 12WF-A (2) to cartridge 12WF (1).
   (4) Make sure that the work area is clean and clear of tools and other items.
   (5) Close access door 314AR (Ref. AMM TASK 52-41-23-410-801).
   (6) Remove the access platform(s).
Subtask 26-22-00-865-061-A
C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUAPU/APU/CTL2KDL42
121VUAPU/ECB/SPLY1KDL41
121VUAPU/FIRE/EXTIG/SQUIB/B2WFL39
121VUAPU/FIRE/EXTIG/SQUIB/A1WFL38
Subtask 26-22-00-710-090-A
D. Operational Test
   (1) Do the operational test of the APU Fire-Extinguishing Loop/Squib (Ref. AMM TASK 26-22-00-710-001)
Subtask 26-22-00-862-054-A
E. Put the aircraft back to its initial configuration.
   (1) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002) or (Ref. AMM TASK 24-41-00-862-002).
[Rev.10 from 2021] 2026.03.31 23:45:31 UTC
"Aviabrain" 2025