DOC AIRBUS | TSM A320FFQIS - FQIC Channels Disagree
TASK 28-42-00-810-849-A
FQIS - FQIC Channels Disagree
A. Referenced Information
3. Fault Confirmation
Subtask 28-42-00-865-082-A ** ON A/C NOT FOR ALL
Subtask 28-42-00-810-098-B ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:07 UTC
FQIS - FQIC Channels Disagree
WARNING:
OBEY THE FUEL SAFETY PROCEDURES.
WARNING:
WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
1. Possible Causes- FQIC [3QT]
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 28-42-34-000-001 | Removal of the Fuel Quantity-Indicating Computer (FQIC) |
| AMM 28-42-34-400-001 | Installation of the Fuel Quantity-Indicating Computer (FQIC) |
Subtask 28-42-00-865-082-A ** ON A/C NOT FOR ALL
A. Table of the circuit breakers used in this procedure:
Subtask 28-42-00-710-098-B ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | FUEL/FQI/CHAN/1 | 1QT | A13 |
| 121VU | FUEL/FQI/CHAN/2 | 2QT | M27 |
B. To keep the number of computer removals to a minimum do the Power On BITE test of the FQI system as follows:
(1) Apply electrical power to the FQI system.
OR (if the FQIS is already powered).
Reset the FQIC. (Open, then after 10 seconds, close the two CBs 1QT and 2QT).
(2) When the BITE test is complete (XX shown on the FQI for 35 seconds and the display has no dashes for 60 seconds) set the MCDU to:
(a) CFDS
(b) SYSTEM REPORT/TEST
(c) FUEL
(d) FQIS STATUS.
(3) Examine the FQIS STATUS page to see if it agrees with the initial defect.
(4) Maintenance steps are not necessary if the three conditions that follow are all correct:
4. Fault Isolation(1) Apply electrical power to the FQI system.
OR (if the FQIS is already powered).
Reset the FQIC. (Open, then after 10 seconds, close the two CBs 1QT and 2QT).
(2) When the BITE test is complete (XX shown on the FQI for 35 seconds and the display has no dashes for 60 seconds) set the MCDU to:
(a) CFDS
(b) SYSTEM REPORT/TEST
(c) FUEL
(d) FQIS STATUS.
(3) Examine the FQIS STATUS page to see if it agrees with the initial defect.
(4) Maintenance steps are not necessary if the three conditions that follow are all correct:
- the CHANNELS DISAGREE 3QT message is not shown
- the Engine/Warning Display FOB reads correctly (XXs not shown)
- the System Display fuel tank temperatures read correctly (XXs not shown).
Subtask 28-42-00-810-098-B ** ON A/C NOT FOR ALL
A. If the CHANNELS DISAGREE 3QT message is shown in Para. 3.B.(3) replace the FQIC [3QT] , AMM 28-42-34-000-001 and AMM 28-42-34-400-001.
NOTE: Make sure that the FQIC to be installed is of the same type as that removed. (Simmons Precision - Sextant Avionique).