DOC AIRBUS | TSM A320FFuel Quantity Probes, Double Probe Failure, ACT 2
TASK 28-42-00-810-872-A
Fuel Quantity Probes, Double Probe Failure, ACT 2
A. Referenced Information
3. Fault Confirmation
Subtask 28-42-00-865-109-A ** ON A/C NOT FOR ALL
Subtask 28-42-00-810-129-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:09 UTC
Fuel Quantity Probes, Double Probe Failure, ACT 2
WARNING:
OBEY THE FUEL SAFETY PROCEDURES.
1. Possible Causes- DOUBLE PROBE FAILURE
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 28-42-00-810-858-A | Fuel Quantity Probe 65QT2, ACT 2 |
| TSM TASK 28-42-00-810-859-A | Fuel Quantity Probe 66QT2, ACT 2 |
| AMM 24-41-00-861-002 | Energize the Aircraft Electrical Circuits from the External Power |
| AMM 28-42-00-740-003 | Interrogation of the FQIS Input Parameters Pages |
| ASM 284209 | |
| AMM 31-32-00-860-001 | Procedure to Get Access to the SYSTEM REPORT/TEST Menu Page |
| AMM 31-60-00-860-001 | EIS Start Procedure |
Subtask 28-42-00-865-109-A ** ON A/C NOT FOR ALL
A. Table of the circuit breakers used in this procedure:
Subtask 28-42-00-710-113-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. Test
(1) To keep the number of computer replacements (with no fault found) to a minimum, do the power on BITE test of the FQIS as follows:
(a) If the FQIS is not energized:
1 Close the C/Bs 1QT and 2QT.
2 Energize the Aircraft Electrical Circuits from the External Power AMM 24-41-00-861-002.
(b) If the FQIS is energized, reset the FQIC as follows:
1 Open the C/Bs 1QT and 2QT.
2 Wait 10 seconds.
3 Close the C/Bs 1QT and 2QT.
(3) On the ECAM control panel, push (in) the FUEL P/BSW.
(4) Make sure that the FUEL page shows on the ECAM lower display unit.
(5) Wait 60 seconds.
(6) Continue as follows:
(b) When the SYSTEM REPORT/TEST menu page comes into view, push the line key adjacent to FUEL.
(c) When the FUEL menu page comes into view, push the line key adjacent to FQIS STATUS.
(7) Examine the FQIS STATUS Page for the message A2 DOUBLE PROBE FAILURE.
(8) Examine the Engine/Warning Display (upper ECAM DU) Fuel On Board (FOB) FQI Fuel Quantity Indication (FQI).
(9) Examine the FUEL System Display (lower ECAM DU) FOB FQI.
(10) If the three conditions that follow are correct, maintenance steps are not necessary:
4. Fault Isolation(1) To keep the number of computer replacements (with no fault found) to a minimum, do the power on BITE test of the FQIS as follows:
(a) If the FQIS is not energized:
1 Close the C/Bs 1QT and 2QT.
2 Energize the Aircraft Electrical Circuits from the External Power AMM 24-41-00-861-002.
(b) If the FQIS is energized, reset the FQIC as follows:
1 Open the C/Bs 1QT and 2QT.
2 Wait 10 seconds.
3 Close the C/Bs 1QT and 2QT.
NOTE: For the FQIC to do a (new) power up BITE test, a power supply interrupt (interval) of more than 10 seconds is necessary. This gives the current status of the FQIS components.
(2) Do the EIS Start Procedure (ECAM only) AMM 31-60-00-860-001. (3) On the ECAM control panel, push (in) the FUEL P/BSW.
(4) Make sure that the FUEL page shows on the ECAM lower display unit.
(5) Wait 60 seconds.
(6) Continue as follows:
NOTE: The FUEL page FQIs will show XXs in amber color, for 35 seconds, during the FQIC power up BITE test.
A FQIS sensor fault must be sensed by the FQIC for 60 seconds before the applicable LRU identification is transmitted to the CFDS as unserviceable. The fault message is shown on the MCDU when set to SYSTEM REPORT/TEST (FUEL) and the FQIS STATUS page.
(a) Do the procedure to get access to the SYSTEM REPORT/TEST menu page AMM 31-32-00-860-001. A FQIS sensor fault must be sensed by the FQIC for 60 seconds before the applicable LRU identification is transmitted to the CFDS as unserviceable. The fault message is shown on the MCDU when set to SYSTEM REPORT/TEST (FUEL) and the FQIS STATUS page.
(b) When the SYSTEM REPORT/TEST menu page comes into view, push the line key adjacent to FUEL.
(c) When the FUEL menu page comes into view, push the line key adjacent to FQIS STATUS.
(7) Examine the FQIS STATUS Page for the message A2 DOUBLE PROBE FAILURE.
(8) Examine the Engine/Warning Display (upper ECAM DU) Fuel On Board (FOB) FQI Fuel Quantity Indication (FQI).
(9) Examine the FUEL System Display (lower ECAM DU) FOB FQI.
(10) If the three conditions that follow are correct, maintenance steps are not necessary:
- the A2 DOUBLE PROBE FAILURE message is not shown
- the Engine/Warning Display FOB FQI reads correctly
- the System Display FOB, and Additional Center Tank 2 (ACT2) FQIs read correctly.
NOTE: The CLASS 1 double probe failure message is given/shown when the two ACT2 FQIS probes fail. Individually the probe faults are CLASS 3.
If the two ACT2 FQIS probes fail there is a cockpit effect, the ACT2 fuel quantity and the FOB show failed (XXs).
(11) If one or more of the three conditions given in step (10) are not correct, go to Para. 4.A. If the two ACT2 FQIS probes fail there is a cockpit effect, the ACT2 fuel quantity and the FOB show failed (XXs).
NOTE: You can get data from the:
- Description and Operation (D and O) section of the Aircraft Maintenance Manual (AMM), Chap. 28-42-00, the Fuel Quantity Indicating System (FQIS)
- Trouble-shooting Manual (TSM) - Task Supporting Data (Ref. P. Block 301)
- Aircraft Schematic Manual (ASM) ASM 284209.
NOTE: You can get more Trouble-shooting data from the CFDS(FUEL):
- Input Parameters Page 3, the ACT PROBE CAPACITANCES AMM 28-42-00-740-003
- FQIC Trouble Shooting Data (Ref. P. Block 301).
Subtask 28-42-00-810-129-A ** ON A/C NOT FOR ALL
A. Procedure
(1) Troubleshoot the two ACT2 FQIS probes:
(1) Troubleshoot the two ACT2 FQIS probes:
- Fuel Quantity Probe 65QT2, ACT 2 (Ref. TSM TASK 28-42-00-810-858)
- Fuel Quantity Probe 66QT2, ACT 2 (Ref. TSM TASK 28-42-00-810-859).