DOC AIRBUS | TSM A320FFuel Quantity - Preselector 5QT
TASK 28-42-00-810-823-A
Fuel Quantity - Preselector 5QT
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 28-42-00-865-104-A
Subtask 28-42-00-810-072-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:29:00 UTC
Fuel Quantity - Preselector 5QT
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- C/B-FUEL/FQI/CHANNEL/1 AND 2 [8QT]
- aircraft wiring
- PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT]
- RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU]
- CTL PNL-REFUEL/DEFUEL [800VU]
- SW-TEST/LTS/HIGH [2QJ]
diode between pins 4 and 3 (part of diode module 4001VD) - FQIC [3QT]
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | MULTIMETER - STANDARD |
| REFERENCE | DESIGNATION |
|---|---|
| ASM 282503 | |
| AMM 28-25-55-000-001 | Removal of the Refuel Panel |
| AMM 28-25-55-400-001 | Installation of the Refuel Panel |
| AMM 28-42-00-710-001 | Operational Test of the Fuel Quantity Indicating-System |
| AMM 28-42-00-740-001 | Status Report (BITE) |
| AMM 28-42-00-740-003 | Interrogation of the FQIS Input Parameters Pages |
| ASM 284203 | |
| AMM 28-42-21-000-001 | Removal of the Fuel Quantity Preselector |
| AMM 28-42-21-400-001 | Installation of the Fuel Quantity Preselector |
| 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) |
| AMM 31-32-00-860-001 | Procedure to Get Access to the SYSTEM REPORT/TEST Menu Page |
Subtask 28-42-00-865-104-A
A. Table of the circuit breakers used in this procedure:
Subtask 28-42-00-710-072-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 121VU | FUEL/FQI/CHANNEL/1 AND 2 | 8QT | L26 |
B. Test
(2) Look at the status report (BITE) of the fuel quantity indication system AMM 28-42-00-740-001.
(3) If the preselector operates as specified in the operational test and the message PRESELECTOR 5QT is not shown on the FQIS STATUS page, no maintenance steps are necessary.
(4) If the preselector LEDs do not come on at preselector power-up or the message PRESELECTOR 5QT is shown on the FQIS STATUS page:
4. Fault IsolationNOTE: The Preselector (5QT) is only operational (electrically powered) when the refuel door is open. The Preselector Power On BITE tests are done at Preselector power on.
(1) Do an operational test of the fuel quantity preselector lights AMM 28-42-00-710-001. (2) Look at the status report (BITE) of the fuel quantity indication system AMM 28-42-00-740-001.
(3) If the preselector operates as specified in the operational test and the message PRESELECTOR 5QT is not shown on the FQIS STATUS page, no maintenance steps are necessary.
(4) If the preselector LEDs do not come on at preselector power-up or the message PRESELECTOR 5QT is shown on the FQIS STATUS page:
- go to Para. 4.A.
- go to Para. 4.B.
- go to Para. 4.C.
- go to Para. 4.D.
Subtask 28-42-00-810-072-A ** ON A/C NOT FOR ALL
A. Procedure - The Preselector LEDs Do Not Come On At Preselector Power-up OR The Message PRESELECTOR 5QT Is Shown On The FQIS STATUS Page
(1) Examine the LEDs on the IND-FUEL QTY MULTI TANK (6QT).
(a) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are on, go to step (7).
(3) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(4) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(5) Examine bit 7R (28VDC FUELLING BUS 2, ON).
(a) If bit 7R shows a 1 (is on), go to step (6).
(b) If bit 7R shows a 0 (is off):
1 Do a check of and close or replace (if necessary) the C/B-FUEL/FQI/CHANNEL/1 AND 2 [8QT] .
2 Do a check of the aircraft wiring (28VDC FUELLING BUS 2 electrical wire) between the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT) and the FQIC (3QT) rack connector AB, pin 9D ASM 284203.
3 Repair all the unserviceable wiring and connectors.
4 Do the tests given in Para. 3.B.
(6) Examine bit 5R (TX FAULT/PRESELECTOR NOT POWERED).
(a) If bit 5R shows a 0 (is on/no TX fault), replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) If bit 5R shows a 1 (is off/TX fault), go to step (7).
(7) Remove the preselector (5QT) AMM 28-42-21-000-001.
(8) Use a MULTIMETER - STANDARD to do a test, at the preselector end connector (5QT-A), to make sure that the 28VDC is available between pin E (+ve) and pin D (-ve).
(9) If the 28VDC is available between pin E and pin D of end connector 5QT-A, replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(10) If the 28VDC is not available between pin E and pin D of end connector 5QT-A:
(a) Do a check of and replace, if necessary, the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
(b) Do a check of the aircraft wiring (28VDC supply) ASM 284203 between:
(d) Repair all the unserviceable wiring and connectors.
(e) Do the tests given in Para. 3.B.
(11) If the fault continues:
(a) Do a check of the aircraft wiring (ARINC 429 BUS electrical wires) ASM 284203 between:
(c) Do the tests given in Para. 3.B.
Subtask 28-42-00-810-072-B ** ON A/C NOT FOR ALL (1) Examine the LEDs on the IND-FUEL QTY MULTI TANK (6QT).
(a) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are on, go to step (7).
NOTE: This shows the C/B-8QT is closed, the RL-14QU energized and 28VDC available.
(b) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are off, go to step (2). NOTE: This shows the C/B-8QT is open, or a common 28VDC power supply failure.
(2) On the MCDU go to SYSTEM REPORT/TEST - FUEL AMM 31-32-00-860-001. (3) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(4) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(5) Examine bit 7R (28VDC FUELLING BUS 2, ON).
(a) If bit 7R shows a 1 (is on), go to step (6).
(b) If bit 7R shows a 0 (is off):
1 Do a check of and close or replace (if necessary) the C/B-FUEL/FQI/CHANNEL/1 AND 2 [8QT] .
2 Do a check of the aircraft wiring (28VDC FUELLING BUS 2 electrical wire) between the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT) and the FQIC (3QT) rack connector AB, pin 9D ASM 284203.
3 Repair all the unserviceable wiring and connectors.
4 Do the tests given in Para. 3.B.
(6) Examine bit 5R (TX FAULT/PRESELECTOR NOT POWERED).
(a) If bit 5R shows a 0 (is on/no TX fault), replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) If bit 5R shows a 1 (is off/TX fault), go to step (7).
(7) Remove the preselector (5QT) AMM 28-42-21-000-001.
(8) Use a MULTIMETER - STANDARD to do a test, at the preselector end connector (5QT-A), to make sure that the 28VDC is available between pin E (+ve) and pin D (-ve).
(9) If the 28VDC is available between pin E and pin D of end connector 5QT-A, replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(10) If the 28VDC is not available between pin E and pin D of end connector 5QT-A:
(a) Do a check of and replace, if necessary, the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
(b) Do a check of the aircraft wiring (28VDC supply) ASM 284203 between:
- the end connector 5QT-A, pin E and the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION (14QU), terminal B1
- the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION (14QU), terminal B2 and the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT).
(d) Repair all the unserviceable wiring and connectors.
(e) Do the tests given in Para. 3.B.
(11) If the fault continues:
(a) Do a check of the aircraft wiring (ARINC 429 BUS electrical wires) ASM 284203 between:
- the FQIC (3QT) rack connector AB, pin 12A and the preselector end connector 5QT-A, pin B
- the FQIC (3QT) rack connector AB, pin 13A and the preselector end connector 5QT-A, pin C.
(c) Do the tests given in Para. 3.B.
A. Procedure - The Preselector LEDs Do Not Come On At Preselector Power-up OR The Message PRESELECTOR 5QT Is Shown On The FQIS STATUS Page
(1) Examine the LEDs on the IND-FUEL QTY MULTI TANK (6QT).
(a) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are on, go to step (7).
(3) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(4) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(5) Examine bit 2D (28VDC FUELLING BUS 2, ON).
(a) If bit 2D shows a 1 (is on), go to step (6).
(b) If bit 2D shows a 0 (is off):
1 Do a check of and close or replace (if necessary) the C/B-FUEL/FQI/CHANNEL/1 AND 2 [8QT] .
2 Do a check of the aircraft wiring (28VDC FUELLING BUS 2 electrical wire) between the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT) and the FQIC (3QT) rack connector AC, pin 9E ASM 284203.
3 Repair all the unserviceable wiring and connectors.
4 Do the tests given in Para. 3.B.
(6) Examine bit 2L (TX FAULT/PRESELECTOR NOT POWERED).
(a) If bit 2L shows a 0 (is on/no TX fault), replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) If bit 2L shows a 1 (is off/TX fault), go to step (7).
(7) Remove the preselector (5QT) AMM 28-42-21-000-001.
(8) Use a MULTIMETER - STANDARD to do a test, at the preselector end connector (5QT-A), to make sure that the 28VDC is available between pin E (+ve) and pin D (-ve).
(9) If the 28VDC is available between pin E and pin D of end connector 5QT-A, replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(10) If the 28VDC is not available between pin E and pin D of end connector 5QT-A:
(a) Do a check of and replace, if necessary, the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
(b) Do a check of the aircraft wiring (28VDC supply) ASM 284203 between:
(d) Repair all the unserviceable wiring and connectors.
(e) Do the tests given in Para. 3.B.
(11) If the fault continues:
(a) Do a check of the aircraft wiring (ARINC 429 BUS electrical wires) ASM 284203 between:
(c) Do the tests given in Para. 3.B.
Subtask 28-42-00-810-119-A (1) Examine the LEDs on the IND-FUEL QTY MULTI TANK (6QT).
(a) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are on, go to step (7).
NOTE: This shows the C/B-8QT is closed, the RL-14QU energized and 28VDC available.
(b) If the LEDs on the IND-FUEL QTY MULTI TANK (6QT) are off, go to step (2). NOTE: This shows the C/B-8QT is open, or a common 28VDC power supply failure.
(2) On the MCDU go to SYSTEM REPORT/TEST - FUEL AMM 31-32-00-860-001. (3) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(4) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(5) Examine bit 2D (28VDC FUELLING BUS 2, ON).
(a) If bit 2D shows a 1 (is on), go to step (6).
(b) If bit 2D shows a 0 (is off):
1 Do a check of and close or replace (if necessary) the C/B-FUEL/FQI/CHANNEL/1 AND 2 [8QT] .
2 Do a check of the aircraft wiring (28VDC FUELLING BUS 2 electrical wire) between the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT) and the FQIC (3QT) rack connector AC, pin 9E ASM 284203.
3 Repair all the unserviceable wiring and connectors.
4 Do the tests given in Para. 3.B.
(6) Examine bit 2L (TX FAULT/PRESELECTOR NOT POWERED).
(a) If bit 2L shows a 0 (is on/no TX fault), replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) If bit 2L shows a 1 (is off/TX fault), go to step (7).
(7) Remove the preselector (5QT) AMM 28-42-21-000-001.
(8) Use a MULTIMETER - STANDARD to do a test, at the preselector end connector (5QT-A), to make sure that the 28VDC is available between pin E (+ve) and pin D (-ve).
(9) If the 28VDC is available between pin E and pin D of end connector 5QT-A, replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(10) If the 28VDC is not available between pin E and pin D of end connector 5QT-A:
(a) Do a check of and replace, if necessary, the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
(b) Do a check of the aircraft wiring (28VDC supply) ASM 284203 between:
- the end connector 5QT-A, pin E and the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION (14QU), terminal B1
- the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION (14QU), terminal B2 and the C/B-FUEL/FQI/CHANNEL/1 and 2 (8QT).
(d) Repair all the unserviceable wiring and connectors.
(e) Do the tests given in Para. 3.B.
(11) If the fault continues:
(a) Do a check of the aircraft wiring (ARINC 429 BUS electrical wires) ASM 284203 between:
- the FQIC (3QT) rack connector AB, pin 6F and the preselector end connector 5QT-A, pin B
- the FQIC (3QT) rack connector AB, pin 6E and the preselector end connector 5QT-A, pin C.
(c) Do the tests given in Para. 3.B.
B. Procedure - A Single LED (Or Segment Of), The CKPT Legend Or The END Legend Fail To Come On When The TEST Switch Set Is To LTS
(1) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
Subtask 28-42-00-810-120-A (1) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
C. Procedure - The Preselector LEDs, The CKPT And The END Legends Do Not Come On When The TEST Switch (2QJ) Is Set To LTS
(1) Examine the indicator (6QT) LEDs while the TEST switch is set to LTS.
(a) If the indicator (6QT) LEDs are also off, do steps (2) thru (5).
(a) The SW-TEST/LTS/HIGH [2QJ] .
(b) Thediode between pins 4 and 3 (part of diode module 4001VD) .
(4) Do a check of the CTL PNL-REFUEL/DEFUEL (800VU) wiring ASM 282503 between the connections and components, as shown in the table that follows:
(a) Repair all the unserviceable wiring and connectors.
(b) Do the tests given in Para. 3.B.
(5) If the fault continues:
(a) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) Do a check of the aircraft wiring ASM 284203 between:
(d) Do the tests given in Para. 3.B.
(6) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(7) Do a check of the aircraft wiring ASM 284203 between:
(b) Do the tests given in Para. 3.B.
(8) Replace the CTL PNL-REFUEL/DEFUEL [800VU] AMM 28-25-55-000-001 and AMM 28-25-55-400-001.
(9) If due to airline operational conditions it is not possible to replace the CTL PNL-REFUEL/DEFUEL (800VU) do the internal trouble-shooting as follows:
(a) Do a check of and replace, if necessary:
1 The SW-TEST/LTS/HIGH [2QJ] .
2 Thediode between pins 4 and 3 (part of diode module 4001VD) .
(b) Do a check of the CTL PNL-REFUEL/DEFUEL (800VU) wiring ASM 282503 between the connections and components, as shown in the table that follows:
(c) Repair all the unserviceable wiring and connectors.
(d) Do the tests given in Para. 3.B.
Subtask 28-42-00-810-121-A ** ON A/C NOT FOR ALL (1) Examine the indicator (6QT) LEDs while the TEST switch is set to LTS.
(a) If the indicator (6QT) LEDs are also off, do steps (2) thru (5).
NOTE: This points to a failure of the LTS TEST command input at 2QJ.
(b) If the indicator (6QT) LEDs are on, do steps (6) thru (9). NOTE: This shows the LTS TEST command input at 2QJ is OK.
(2) Replace the CTL PNL-REFUEL/DEFUEL [800VU] AMM 28-25-55-000-001 and AMM 28-25-55-400-001. NOTE: If due to airline operational conditions it is not possible to replace the CTL PNL-REFUEL/DEFUEL (800VU) and internal trouble-shooting is required, do steps (3) and (4).
(3) Do a check of and replace, if necessary: (a) The SW-TEST/LTS/HIGH [2QJ] .
(b) The
(4) Do a check of the CTL PNL-REFUEL/DEFUEL (800VU) wiring ASM 282503 between the connections and components, as shown in the table that follows:
NOTE: The circuit connections shown in the table are abbreviated, for example:
- the connector 4023VC, pin <A is shown as 4023VC-<A
- the diode module 4001VD, terminal 3 is shown as 4001VD-3
- the terminal block 4001VT, terminal 4K is shown as 4001VT-4K.
| ----------------------------------------------------------------------------- |
| ! CONNECTOR-PIN ! COMPONENT TO COMPONENT ! CONNECTOR-PIN ! |
| !-----------------------------------------------------------------------------! |
| ! 4023VC-<A --------------------------------------- 4001VD-3 ! |
| ! 4001VD-4 ------------------------ 4001VT-4K ! |
| ! 4001VT-4B ----------------------- 2QJ-3A ! |
| ! 2QJ-1A -------------------------------------- 4024VC-<J ! |
| ----------------------------------------------------------------------------- |
(a) Repair all the unserviceable wiring and connectors.
(b) Do the tests given in Para. 3.B.
(5) If the fault continues:
(a) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(b) Do a check of the aircraft wiring ASM 284203 between:
- the preselector end connector 5QT-A, pin R and the CTL PNL-REFUEL/DEFUEL (800VU) end connector 4023VC-A, pin <A (LED TEST electric wire)
- the CTL PNL-REFUEL/DEFUEL (800VU) end connector 4024VC-A, pin <J and the aircraft ground.
(d) Do the tests given in Para. 3.B.
(6) Replace the PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
(7) Do a check of the aircraft wiring ASM 284203 between:
- the preselector end connector 5QT-A, pin R and the CTL PNL-REFUEL/DEFUEL (800VU) end connector 4023VC-A, pin <A (LED TEST electric wire)
- the CTL PNL-REFUEL/DEFUEL (800VU) end connector 4024VC-A, pin <J and the aircraft ground.
(b) Do the tests given in Para. 3.B.
(8) Replace the CTL PNL-REFUEL/DEFUEL [800VU] AMM 28-25-55-000-001 and AMM 28-25-55-400-001.
(9) If due to airline operational conditions it is not possible to replace the CTL PNL-REFUEL/DEFUEL (800VU) do the internal trouble-shooting as follows:
(a) Do a check of and replace, if necessary:
1 The SW-TEST/LTS/HIGH [2QJ] .
2 The
(b) Do a check of the CTL PNL-REFUEL/DEFUEL (800VU) wiring ASM 282503 between the connections and components, as shown in the table that follows:
NOTE: The circuit connections shown in the table are abbreviated, for example:
- the connector 4023VC, pin <A is shown as 4023VC-<A
- the diode module 4001VD, terminal 3 is shown as 4001VD-3
- the terminal block 4001VT, terminal 4K is shown as 4001VT-4K.
| ----------------------------------------------------------------------------- |
| ! CONNECTOR-PIN ! COMPONENT TO COMPONENT ! CONNECTOR-PIN ! |
| !-----------------------------------------------------------------------------! |
| ! 4023VC-<A --------------------------------------- 4001VD-3 ! |
| ! 4001VD-4 ------------------------ 4001VT-4K ! |
| ! 4001VT-4B ----------------------- 2QJ-3A ! |
| ! 2QJ-1A -------------------------------------- 4024VC-<J ! |
| ----------------------------------------------------------------------------- |
(c) Repair all the unserviceable wiring and connectors.
(d) Do the tests given in Para. 3.B.
D. Procedure - The Preselector PRESELECTED Fuel Quantity Fails To Change When The INC/DEC Switch Is Set To INC Or DEC
(2) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(3) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(4) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to INC.
(6) Release the preselector INC/DEC switch.
(7) If during the time the INC/DEC is set to INC:
(a) The bit 8Q shows a 1 go to step (8).
(b) The bit 8Q shows a 0:
1 Do a check of the aircraft wiring (INCREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin L and the FQIC (3QT) rack connector AB, pin 2E.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(8) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to DEC.
(10) Release the preselector INC/DEC switch.
(11) If during the time the INC/DEC is set to DEC:
(a) The bit 7Q shows a 1 go to step (12).
(b) The bit 7Q shows a 0:
1 Do a check of the aircraft wiring (DECREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin M and the FQIC (3QT) rack connector AB, pin 4E.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(12) If the fault continues:
(a) Do a check of and replace, if necessary:
1 The PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
2 The FQIC [3QT] AMM 28-42-34-000-001 and AMM 28-42-34-400-001.
(b) Do a check of the aircraft wiring (INC/DEC common electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin K and the FQIC (3QT) rack connector AB, pin 3E.
1 Repair all the unserviceable wiring and connectors.
(c) Do the tests given in Para. 3.B.
Subtask 28-42-00-810-121-B ** ON A/C NOT FOR ALL NOTE: The preselector PRESELECTED fuel quantity must first be increased from the ACTUAL fuel quantity before it can be decreased. This is because the PRESELECTED fuel quantity cannot be set to less than the ACTUAL fuel quantity.
(1) On the MCDU go to SYSTEM REPORT/TEST - FUEL AMM 31-32-00-860-001. (2) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(3) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(4) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to INC.
NOTE: This step requires a second person.
(5) Examine the bit 8Q (PRESELECTOR 5QT INCREMENT). (6) Release the preselector INC/DEC switch.
(7) If during the time the INC/DEC is set to INC:
(a) The bit 8Q shows a 1 go to step (8).
(b) The bit 8Q shows a 0:
1 Do a check of the aircraft wiring (INCREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin L and the FQIC (3QT) rack connector AB, pin 2E.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(8) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to DEC.
NOTE: This step requires a second person.
(9) Examine the bit 7Q (PRESELECTOR 5QT DECREMENT). (10) Release the preselector INC/DEC switch.
(11) If during the time the INC/DEC is set to DEC:
(a) The bit 7Q shows a 1 go to step (12).
(b) The bit 7Q shows a 0:
1 Do a check of the aircraft wiring (DECREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin M and the FQIC (3QT) rack connector AB, pin 4E.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(12) If the fault continues:
(a) Do a check of and replace, if necessary:
1 The PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
2 The FQIC [3QT] AMM 28-42-34-000-001 and AMM 28-42-34-400-001.
(b) Do a check of the aircraft wiring (INC/DEC common electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin K and the FQIC (3QT) rack connector AB, pin 3E.
1 Repair all the unserviceable wiring and connectors.
(c) Do the tests given in Para. 3.B.
D. Procedure - The Preselector PRESELECTED Fuel Quantity Fails To Change When The INC/DEC Switch Is Set To INC Or DEC
(2) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(3) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(4) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to INC.
(6) Release the preselector INC/DEC switch.
(7) If during the time the INC/DEC is set to INC:
(a) The bit 2Q shows a 1 go to step (8).
(b) The bit 2Q shows a 0:
1 Do a check of the aircraft wiring (INCREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin L and the FQIC (3QT) rack connector AC, pin 4K.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(8) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to DEC.
(10) Release the preselector INC/DEC switch.
(11) If during the time the INC/DEC is set to DEC:
(a) The bit 2R shows a 1 go to step (12).
(b) The bit 2R shows a 0:
1 Do a check of the aircraft wiring (DECREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin M and the FQIC (3QT) rack connector AC, pin 4J.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(12) If the fault continues:
(a) Do a check of and replace, if necessary:
1 The PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
2 The FQIC [3QT] AMM 28-42-34-000-001 and AMM 28-42-34-400-001.
NOTE: The preselector PRESELECTED fuel quantity must first be increased from the ACTUAL fuel quantity before it can be decreased. This is because the PRESELECTED fuel quantity cannot be set to less than the ACTUAL fuel quantity.
(1) On the MCDU go to SYSTEM REPORT/TEST - FUEL AMM 31-32-00-860-001. (2) Do the Interrogation of the FQIS Input Parameter Pages AMM 28-42-00-740-003.
(3) Go to the Input Parameters Page 3 - FQIS DISCRETE INPUTS.
(4) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to INC.
NOTE: This step requires a second person.
(5) Examine the bit 2Q (PRESELECTOR 5QT INCREMENT). (6) Release the preselector INC/DEC switch.
(7) If during the time the INC/DEC is set to INC:
(a) The bit 2Q shows a 1 go to step (8).
(b) The bit 2Q shows a 0:
1 Do a check of the aircraft wiring (INCREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin L and the FQIC (3QT) rack connector AC, pin 4K.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(8) At the external REFUEL/DEFUEL control panel, have the preselector 5QT INC/DEC switch set, and held, to DEC.
NOTE: This step requires a second person.
(9) Examine the bit 2R (PRESELECTOR 5QT DECREMENT). (10) Release the preselector INC/DEC switch.
(11) If during the time the INC/DEC is set to DEC:
(a) The bit 2R shows a 1 go to step (12).
(b) The bit 2R shows a 0:
1 Do a check of the aircraft wiring (DECREMENT electrical wire) ASM 284203 between the preselector end connector 5QT-A, pin M and the FQIC (3QT) rack connector AC, pin 4J.
2 Repair all the unserviceable wiring and connectors.
3 Do the tests given in Para. 3.B.
(12) If the fault continues:
(a) Do a check of and replace, if necessary:
1 The PRESELECTOR-FUEL QUANTITY, MULTI TANK [5QT] AMM 28-42-21-000-001 and AMM 28-42-21-400-001.
2 The FQIC [3QT] AMM 28-42-34-000-001 and AMM 28-42-34-400-001.