W DOC AIRBUS | TSM A320F

Spurious TCMA Arming on Engine 1

TASK 73-20-00-810-982-A
Spurious TCMA Arming on Engine 1

1. Possible Causes
  • Relay (28KS1)
  • EIU-1 [1KS1]
  • Relay (27KS1)
  • SEC1
  • SEC2
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 27-94-34-000-001
Removal of the SEC
AMM 27-94-34-400-001
Installation of the SEC
ASM 732508
ASM 732523
AMM 73-25-34-000-040
Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040
Installation of the Engine Interface Unit (EIU)
3. Fault Confirmation
Subtask 73-20-00-710-334-A ** ON A/C NOT FOR ALL
A. Test
  • On the overhead panel 50VU, push the FADEC GND PWR 1 pushbutton switch.
  • Put the throttle control levers in the TO/GA position.
  • On the left or right MCDU, get access to the ENGINE MAIN MENU screen.
  • On the MCDU, push the line key (4R) adjacent to the applicable Specific tests indication.
  • push the line key (5L) adjacent to the SEC RELAY STATUS:
   (1) If MCDU screen indicates SEC RELAY OPEN, the failure is not confirmed.
  • No further action is required
   (2) If MCDU screen indicates SEC RELAY CLOSED, the failure is confirmed.
  • Do the step 4. Fault Isolation
4. Fault Isolation
Subtask 73-20-00-810-284-A ** ON A/C NOT FOR ALL
A. If MCDU screen indicates SEC RELAY CLOSED:
  • Pull C/B 24KS1
  • Push the line key (6L) adjacent to "RETURN" and re-select the SEC RELAY STATUS page:
   (1) If MCDU screen indicates SEC RELAY CLOSED:
  • Replace the Relay (28KS1).
     (a) If the fault continues:
  • Remove the EIU
  • Do a check for a ground signal at pin E2 of the EIU rack-connector AA:
       1 If there is no ground signal:
       2 If there is a ground signal:
  • Repair the wiring between EIU connector AA and 28KS1 ASM 732508.
   (2) If MCDU screen indicates SEC RELAY OPEN:
  • Replace the Relay (27KS1).
     (a) If the fault continues:
  • Pull C/B 21CE1 and 21CE2.
  • Push the line key (6L) adjacent to "RETURN" and re-select the SEC RELAY STATUS page:
       1 If SEC RELAY CLOSED is displayed:
  • Repair the wiring between SEC1/2 and 27KS1 ASM 732523.
       2 If SEC RELAY OPEN is displayed:
  • push back C/B 21CE1 and Re-select MCDU SEC RELAY STATUS page:
         a If SEC RELAY CLOSED is displayed:
         b If SEC RELAY OPEN is displayed:
Subtask 73-20-00-710-335-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:35:32 UTC
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