W DOC AIRBUS | TSM A320F

Spurious TCMA Arming on Engine 1

TASK 73-20-00-810-980-A
Spurious TCMA Arming on Engine 1

1. Possible Causes
  • Relay (28KS1)
  • EIU-1 [1KS1]
  • Relay (27KS1)
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
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 73-20-00-710-330-A ** ON A/C NOT FOR ALL
A. Test
NOTE: The landing gear must be correctly compressed without any tools or maintenance action.
  • On the overhead panel 50VU, push the FADEC GND PWR 1 pushbutton switch.
  • Put the throttle control levers in the idle 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 CLOSED, the failure is not confirmed.
  • No further action is required
   (2) If MCDU screen indicates SEC RELAY OPEN, the failure is confirmed.
  • Do the step 4. Fault Isolation
4. Fault Isolation
Subtask 73-20-00-810-282-A ** ON A/C NOT FOR ALL
A. If MCDU screen indicates SEC RELAY OPEN:
  • 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 (2L) adjacent to the ECU RELAY 1+2 CTRL:
   (1) If fault light located on the Engine Panel Unit (115VU) is illuminated:
  • 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 a ground signal:
       2 If there is no ground signal:
  • Repair the wiring between EIU connector AA and 28KS1 ASM 732508.
   (2) If fault light located on the Engine Panel Unit (115VU) is not illuminated:
  • Replace the Relay (27KS1).
     (a) If the fault continues:
  • Replace the Relay (28KS1).
     (b) 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 a ground signal:
       2 If there is no ground signal:
  • Remove the 28KS1
  • Do a check for a ground signal:
    . at pin C of the 28KS1 connector A:
    . at pin Z of the 28KS1 connector A:
         a If there is no ground signal:
  • repair the wiring as required
         b If there is a ground signal:
  • Do a check of continuity between pin 6 of 28KS1 connector A and pin E2 of the EIU rack-connector AA:

    * If there is no continuity:
    - repair the wiring between EIU and 28KS1 ASM 732508

    * If there is continuity:
    - remove 27KS1
    - do a check for a 28V at pin X of the 27KS1 connector A:

    ** If there is 28V:
    - repair the wiring between SEC1/2 and 27KS1 ASM 732523

    ** If there is not 28V:
    - repair the wiring as required ASM 732523
Subtask 73-20-00-710-331-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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