W DOC AIRBUS | TSM A320F

System Inhibited by External Signal

TASK 21-58-00-810-818-A
System Inhibited by External Signal

1. Possible Causes
  • wiring
  • CSAS CONTROL UNIT [100HW]
  • PROX SNSR-L L/G EXT, SYS 1 [21GA]
  • PROX SNSR-L L/G EXT, SYS 2 [23GA]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
ASM 215301
AMM 21-58-00-710-001
Operational Test of the Conditioned Service Air System without Bleed Air
AMM 21-58-34-000-001
Removal of the CSAS Control Unit
AMM 21-58-34-400-001
Installation of the CSAS Control Unit
AMM 31-36-00-740-008
Access to the Parameter Call-Up Menus
ASM 315402
AMM 32-31-73-000-001
Removal of the MLG Proximity-Sensors
AMM 32-31-73-200-001
Inspection of the MLG Proximity Sensor and Target Clearances
AMM 32-31-73-400-001
Installation of the MLG Proximity-Sensors
3. Fault Confirmation
Subtask 21-58-00-710-084-A ** ON A/C NOT FOR ALL
A. Test.
   (1) At the overhead panel 20VU, make sure that the ENG 1 FIRE pushbutton switch (on the ENG/APU FIRE PANEL 1WD) is in the closed and guarded position.
NOTE: It is not necessary to do further trouble shooting if the flight or maintenance log books show that the flight crew or the maintenance personnel pushed the ENG 1 FIRE pushbutton switch on the ENG/APU FIRE panel after an engine-fire condition.
   (2) Do the operational test of the conditioned service air system without bleed air AMM 21-58-00-710-001.
   (3) Do a read out of the post flight report.
4. Fault Isolation
Subtask 21-58-00-810-067-A ** ON A/C NOT FOR ALL
A. If the test gives a different maintenance message, do the related trouble shooting procedure.
Subtask 21-58-00-810-092-A ** ON A/C NOT FOR ALL
B. If the test or the post flight report gives the maintenance message SYSTEM INHIBITED BY EXTERNAL SIGNAL:
  • do a read out of the TROUBLE SHOOTING DATA (TSD) of the fault message:
   (1) push the line key adjacent to the prompt ">" at the right of the Class number of the fault:
     (a) if the trouble shooting data gives the fault code A000: refer to paragraph C.
     (b) if the trouble shooting data gives the fault code A001: refer to paragraph D.
Subtask 21-58-00-810-093-A ** ON A/C NOT FOR ALL
C. If the trouble shooting data gives the fault code A000:
  • do a check for ground signal at pin AA/J6 of the CSAS CONTROL UNIT (100HW).
   (1) If there is no ground signal:
  • do a check and repair the wiring from the CSAS CONTROL UNIT (100HW) to the ENG/APU FIRE PANEL (1WD) ASM 215301.
   (2) If there is a ground signal:
Subtask 21-58-00-810-080-A ** ON A/C NOT FOR ALL
D. If the trouble shooting data gives the fault code A001:
  • read the AIDS data AMM 31-36-00-740-008 for:
    the Essential Landing Gear - ESS LG COMPRESSED signal = DMU Para. No.
    .029.1.002.01.22

    the Norm Landing Gear - NORM LG COMPRESSED signal = DMU Para. No.
    .029.1.002.10.22

   (1) If the result is:
ESS LG COMPRESSED = 1
  • do a check and repair the wiring between:
    SDAC 1 (1WV1) AB/7A and LGCIU 1 (5GA1) AB/3F ASM 315402.
     (a) If the fault continues:
     (b) If the fault continues:
     (c) If the fault continues:
  • do the trouble shooting of the landing gear (Ref. TSM CH32).
   (2) If the result is:
NORM LG COMPRESSED = 1
  • do a check and repair the wiring between:
    SDAC 1 (1WV1) AD/7G and LGCIU 2 (5GA2) AB/3F ASM 315402.
     (a) If the fault continues:
     (b) If the fault continues:
     (c) If the fault continues:
  • do the trouble shooting of the landing gear (Ref. TSM CH32).
Subtask 21-58-00-810-094-A ** ON A/C NOT FOR ALL
E. If the fault continues after the subsequent flight:
  • do a check and repair the wiring between:
    SDAC 1 (1WV1) AB/7A and LGCIU 1 (5GA1) AB/3F,
    SDAC 1 (1WV1) AD/7G and LGCIU 2 (5GA2) AB/3F ASM 315402.
   (1) If the fault continues:
   (2) If the fault continues:
  • do the trouble shooting of the landing gear (Ref. TSM CH32).
Subtask 21-58-00-710-085-A ** ON A/C NOT FOR ALL
F. Do the test as given in the Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:24:50 UTC
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