W DOC AIRBUS | TSM A320F

A/THR Pushbutton Switch does not Come on at A/THR Engagement

TASK 22-31-00-810-804-A
A/THR Pushbutton Switch does not Come on at A/THR Engagement

1. Possible Causes
  • FCU [2CA]
  • wiring of the A/THR 2 SW MON and A/THR 2 SW COM discretes (from the FCU (2CA) to the first terminal block)
  • wiring of the A/THR 1 SW MON and A/THR 1 SW COM discretes (from the FCU (2CA) to the first terminal block)
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
ASM 223101
AMM 22-81-12-000-001
Removal of the FCU
AMM 22-81-12-400-001
Installation of the FCU
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002
De-energize the Aircraft Electrical Circuits Supplied from the External Power
3. Fault Confirmation
Subtask 22-31-00-860-052-A
A. Job Set-up
   (1) Aircraft Maintenance Configuration
     (a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
Subtask 22-31-00-865-053-A
B. Make sure that this(these) circuit breaker(s) is(are) closed:
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
49VUAUTO FLT/FCU/19CA1B05
49VUAUTO FLT/FMGC/110CA1B02
121VUAUTO FLT/FCU/29CA2M21
121VUAUTO FLT/FMGC/210CA2M17
Subtask 22-31-00-710-056-A
C. Test
ACTION
RESULT
1.Open the circuit breaker 10CA1.
2.On the FCU:
  • push the A/THR pushbutton switch

The A/THR pushbutton switch comes on.
  • Push the A/THR pushbutton switch.
The A/THR pushbutton switch goes off.
3.Close the circuit breaker 10CA1.
4.Open the circuit breaker 10CA2.
5.On the FCU:
  • push the A/THR pushbutton switch

The A/THR pushbutton switch comes on.
  • Push the A/THR pushbutton switch.
The A/THR pushbutton switch goes off.
4. Fault Isolation
Subtask 22-31-00-810-053-A
A. If the A/THR pushbutton switch does not come on when you open the circuit breaker 10CA1 only:
   (1) If the fault continues:
  • do a check and repair the wiring of the A/THR 2 SW MON and A/THR 2 SW COM discretes (from the FCU (2CA) to the first terminal block) ASM 223101.
Subtask 22-31-00-810-065-A
B. If the A/THR pushbutton switch does not come on when you open the circuit breaker 10CA2 only:
   (1) If the fault continues:
  • do a check and repair the wiring of the A/THR 1 SW MON and A/THR 1 SW COM discretes (from the FCU (2CA) to the first terminal block) ASM 223101.
Subtask 22-31-00-710-057-A
C. Do the test given in Para. 3.
5. Close-up
Subtask 22-31-00-860-053-A
A. Put the aircraft back to its initial configuration.
   (1) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:25:09 UTC
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