DOC AIRBUS | TSM A320FFuel Quantity Probes, Center Tank Double Probe Failure
TASK 28-42-00-810-856-A
Fuel Quantity Probes, Center Tank Double Probe Failure
Subtask 28-42-00-865-087-A ** ON A/C NOT FOR ALL
Subtask 28-42-00-810-102-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:08 UTC
Fuel Quantity Probes, Center Tank Double Probe Failure
WARNING:
OBEY THE FUEL SAFETY PROCEDURES.
1. Possible CausesCenter Tank CLASS 3 probe failures (will be more than one)
Subtask 28-42-00-865-087-A ** ON A/C NOT FOR ALL
A. Table of the circuit breakers used in this procedure:
Subtask 28-42-00-710-102-A ** 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:
3. 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 C DOUBLE PROBE FAILURE message is not shown
- the Engine/Warning Display FOB reads correctly (dashes or XXs not shown)
- the System Display Center Fuel Tank FQI reads correctly (dashes or XXs not shown).
NOTE: The CLASS 1 double probe failure message is given/shown when certain pairs of probes fail which individually are CLASS 3.
If a pair of these related probes fail there is a cockpit effect, either degraded or failed.
More data reference Double Probe Failure can be got from P. Block 301.
If a pair of these related probes fail there is a cockpit effect, either degraded or failed.
More data reference Double Probe Failure can be got from P. Block 301.
Subtask 28-42-00-810-102-A ** ON A/C NOT FOR ALL
A. If the C DOUBLE PROBE FAILURE message is shown in Para. 3.B.(3):
(1) Examine the FQIS STATUS page forCenter Tank CLASS 3 probe failures (will be more than one) .
(2) Make a note of the Center Tank CLASS 3 probe failures shown.
(3) Refer to CFDS message identified in Step (2).
(4) Troubleshoot the identified probes.
(1) Examine the FQIS STATUS page for
(2) Make a note of the Center Tank CLASS 3 probe failures shown.
(3) Refer to CFDS message identified in Step (2).
(4) Troubleshoot the identified probes.