W DOC AIRBUS | TSM A320F

APU SQUIB/DISCH Light Fault

TASK 26-22-00-810-803-A
APU SQUIB/DISCH Light Fault

1. Possible Causes
  • ENG/APU FIRE PNL [1WD]
  • BOTTLE-APU FIRE EXTING [11WF]
  • wiring
  • CARTRIDGE-APU FIRE EXTING BOTTLE [12WF]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 26-12-12-000-001
Removal of the ENG/APU Fire Panel
AMM 26-12-12-400-001
Installation of the ENG/APU Fire Panel
AMM 26-22-00-710-001
Operational Test of the APU Fire-Extinguishing Loop/Squib
ASM 262201
AMM 26-22-41-000-001
Removal of the Fire Extinguisher Bottle
AMM 26-22-41-400-001
Installation of the Fire Extinguisher Bottle
AMM 26-22-42-000-001
Removal of the Fire-Extinguisher Bottle Cartridge
AMM 26-22-42-400-001
Installation of the Fire-Extinguisher Bottle Cartridge
AMM 33-14-00-710-001
Operational Test of the Lights
3. Fault Confirmation
Subtask 26-22-00-710-052-A
A. The APU FIRE EXTINGUISHING PANEL 20VU (p/n 330TS08Y) has a fault. Special operation is necessary. Incorrect operation causes the APU fire extinguisher bottle to discharge. Airbus supplies a new 20VU panel that corrects this fault. See TFU 26.22.00.007 for more data.
   (1) Maintenance recommendation:
     (a) Before the test:
  • Pull the CIRCUIT BREAKER 30WF on panel 120VU.
     (b) During the test:
  • Push the APU FIRE TEST BUTTON quickly and fully.
  • Hold it fully during the test.
  • Release it quickly.
     (c) After the test:
  • Close the CIRCUIT BREAKER 30WF on panel 120VU.
   (2) Do the operational test of the APU fire-extinguishing system AMM 26-22-00-710-001.
4. Fault Isolation
Subtask 26-22-00-810-054-A
A. If the test gives a different maintenance message:
  • Do the trouble shooting procedure related to the maintenance message.
Subtask 26-22-00-810-055-A
B. If the DISCH legend in the AGENT p/bsw does not come on during the test:
   (1) If the test gives a different maintenance message:
  • Do the trouble shooting procedure related to the maintenance message.
   (2) If the fault continues:
   (3) If the fault continues:
   (4) If the fault continues:
  • do a check and repair the wiring if necessary between the:
    PANEL (1WD) connector E/K and BOTTLE (11WF) connector A/C,
    BOTTLE (11WF) connector A/B and GND ASM 262201.
Subtask 26-22-00-810-056-A
C. If the SQUIB legend in the AGENT p/bsw does not come on during the test:
   (1) If the test gives a different maintenance message:
  • Do the trouble shooting procedure related to the maintenance message.
   (2) If the fault continues:
   (3) If the fault continues:
   (4) If the fault continues:
  • do a check and repair the wiring between the:
    CARTRIDGE (12WF) connector A/A and PANEL (1WD) connector E/G,
    CARTRIDGE (12WF) connector A/B and PANEL (1WD) connector F/J,
    CARTRIDGE (12WF) connector A and GND ASM 262201.
Subtask 26-22-00-710-057-A
D. Do the test as given in the Para. 3.A.
5. Close-up
Subtask 26-22-00-860-052-A
A. Put the aircraft back to its initial configuration.
[Rev.8 from Aug 2018] 2026.04.04 04:27:24 UTC
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