DOC AIRBUS | TSM A320FLoss of the Information from the LGCIUs
TASK 21-26-00-810-821-A
Loss of the Information from the LGCIUs
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 21-26-00-865-065-A
Subtask 21-26-00-860-051-A
[Rev.8 from Aug 2018]
2026.04.04 04:24:38 UTC
Loss of the Information from the LGCIUs
1. Possible Causes
- AEVC [10HQ]
- wiring
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 32-31-00-810-802-A | LGCIU Fault |
| AMM 21-26-00-710-001 | Operational Check of the Avionics Equipment Ventilation-System via MCDU |
| AMM 21-26-00-710-008 | Operational Test to Read the CFDS for CLASS 3 Faults of the AEVC |
| AMM 21-26-00-710-009 | Operational Test to Read the CFDS for LAST LEG REPORT of the AEVC |
| ASM 212602 | |
| AMM 21-26-34-000-001 | Removal of the Avionics Equipment Ventilation Computer (AEVC) |
| AMM 21-26-34-400-001 | Installation of the Avionics Equipment Ventilation Computer (AEVC) |
| AMM 24-42-00-861-001 | Energize the Ground Service Network from the External Power |
Subtask 21-26-00-865-065-A
A. Table of the circuit breakers used in this procedure:
Subtask 21-26-00-710-068-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 122VU | AIR COND/AVNCS/VENT/MONG | 3HQ | Y17 |
B. Test
(1) Do a reset of the Avionics Equipment Ventilation Computer (AEVC) (10HQ).
(a) Open the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(b) Wait for ten seconds.
(c) Close the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(2) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
(3) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
(4) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.
4. Fault Isolation(1) Do a reset of the Avionics Equipment Ventilation Computer (AEVC) (10HQ).
(a) Open the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(b) Wait for ten seconds.
(c) Close the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(2) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
(3) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
(4) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.
Subtask 21-26-00-860-051-A
A. Aircraft Maintenance Configuration
(1) Release the EXTRACT pushbutton switch (the Override (OVRD) legend comes on).
(2) Wait for 60 seconds.
(3) Remove the AEVC AMM 21-26-34-000-001.
(4) Install BREAKOUT BOX on the position of 10HQ (AEVC).
(5) Energize the ground service network
AMM 24-42-00-861-001.
(6) If, after the disconnection of the AEVC, the ground scanning give the maintenance message : VENT AVNCS SYS FAULT
Subtask 21-26-00-810-059-A (1) Release the EXTRACT pushbutton switch (the Override (OVRD) legend comes on).
(2) Wait for 60 seconds.
(3) Remove the AEVC AMM 21-26-34-000-001.
(4) Install BREAKOUT BOX on the position of 10HQ (AEVC).
(5) Energize the ground service network
AMM 24-42-00-861-001.
(6) If, after the disconnection of the AEVC, the ground scanning give the maintenance message : VENT AVNCS SYS FAULT
- Ignore this message
B. If the test gives the maintenance message CHECK LGCIU - AEVC INTFC:
Subtask 21-26-00-710-069-A - Do a check for a ground signal at pin AB/9C and pin AB/10C of the AEVC (10HQ) ASM 212602.
- Replace the AEVC [10HQ] AMM 21-26-34-000-001 and AMM 21-26-34-400-001.
- Do a check of the wiring ASM 212602 between:
. Pin AB/9C of the AEVC (10HQ) and pin AB/1D of the LGCIU-1 (5GA1)
. Pin AB/10C of the AEVC (10HQ) and pin AB/1D of the LGCIU-2 (5GA2).
- Repair the related wiring.
- Do the trouble shooting of the LGCIU (Ref. TSM TASK 32-31-00-810-802).
C. Do the operational test given in Para. 3.