Fuel Quantity Probe - A Malfunction in the Wing Tank when Fused Connector Plugs are Installed - An Alternative Task (procedure) for the Connector Plug Only

TASK 28-42-00-810-873-A
Fuel Quantity Probe - A Malfunction in the Wing Tank when Fused Connector Plugs are Installed - An Alternative Task (procedure) for the Connector Plug Only

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

fused connector plug 4041VC-A
fused connector plug 4042VC-A
fused connector plug 4043VC-A
fused connector plug 4044VC-A

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	MULTIMETER - STANDARD
No specific	AR	TESTER - INSULATION, 500 V

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 28-42-00-810-801-A	Fuel Quantity Indication Computer (FQIC) 3QT
AMM 05-25-70-200-004	GENERAL VISUAL INSPECTION OF FALSE SPAR BOX (EWIS)
ESPM 2052210
ESPM 2052240
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
ASM 284205
ASM 284206
ASM 284207
ASM 284208
AMM 28-42-43-000-008	Removal of the Wing Tank Fuel Quantity Indicating Probe Fused/Shorting Plug Connectors
AMM 28-42-43-400-008	Installation of the Wing Tank Fuel Quantity Indicating Probe Fused/Shorting Plug Connectors
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

3. Fault Confirmation
Subtask 28-42-00-865-110-A ** ON A/C NOT FOR ALL

A. Table of the circuit breakers referred to in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	FUEL/FQI/CHAN/1	1QT	A13
121VU	FUEL/FQI/CHAN/2	2QT	M27

Subtask 28-42-00-710-114-A ** ON A/C NOT FOR ALL

B. Test

NOTE: This task gives an alternative procedure (with a different start) for trouble shooting a wing-tank fuel-probe malfunction. It is shown here for the fused connector plugs only.

NOTE: This test (and procedure) is written for a left wing fuel-probe malfuction with the right wing items (FINs) given in parenthesis if applicable.

(1) 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 5 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 5 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.
(b) When the SYSTEM REPORT/TEST menu page comes into view, push the line key adjacent to FUEL.
(c) When the FUEL menu page 1 comes into view, push the NEXT PAGE key on the MCDU keyboard to see the FUEL menu page 2.

NOTE: If a menu has more than one page (shown by the more to come symbol > on the top line, right side of the MCDU display) each operation of the NEXT PAGE key on the MCDU keyboard will cause the next page to be shown. When the last page of any menu is shown, operation of the NEXT PAGE key will cause the first page to be shown.

(d) When the FUEL menu page 2 comes into view, push the line key adjacent to FQIS STATUS.
(7) Examine the FQIS STATUS page.
(8) Make a record of all the wing-tank fuel-probes shown on the FQIS STATUS page.
(a) If the FQIC (3QT) is shown, trouble shoot the Fuel Quantity Indication Computer (FQIC) 3QT (Ref. TSM TASK 28-42-00-810-801) before you do more steps.
(b) If no FQIS messages are shown, maintenance steps are not necessary.
(9) Open the C/Bs 1QT and 2QT.
(10) Remove the access panel 574BB (674BB) located on the lower surface of the wing (false spar box). It is forward of and between flap track 2 and the out board edge of the inner flap AMM 05-25-70-200-004.
(11) Get access through the opening 574BB (674BB).
The fused connector plugs are installed below the tank wall connectors 4039VC1 and 4040VC1 (4039VC2 and 4040VC2).
(12) Swap the positions of the fused connector plugs 4041VC-A and 4043VC-A (4042VC-A and 4044VC-A).
(13) Close the C/Bs 1QT and 2QT.
(14) Do steps (5) thru (8) again.

NOTE: This is necessary because when the C/Bs were set to open and the 28VDC removed from the FQIS in step (9) the CFDS display (on the MCDU) will return to the top menu.

(15) Compare the two FQIS STATUS records that you made.
(16) If the original (reported) FQIS message:
(a) Is shown again (repeated):
1 Do the related troubleshooting procedure for the (identified) fault message shown.

NOTE: This step is applicable to all wing-tank fuel-probe FQIS messages that are shown again after the shorting plugs have changed (swapped) positions.

(b) Changes from that shown in the left column to that shown in the right column of the table that follows:

NOTE: The preamble (FUEL QUANTITY) for class 1 messages has been omitted for clarity.

1 LEFT WING (PLUGS 4041VC-A AND 4043VC-A):

ORIGINAL PROBE MESSAGE	NEW MESSAGE AFTER PLUG CHANGE (SWAP)
L CADENSICON 19QT1	L QTY PROBE 24QT1
L QTY PROBE 21QT1	L QTY PROBE 22QT1
L QTY PROBE 22QT1	L QTY PROBE 21QT1
L QTY PROBE 23QT1	L QTY PROBE 24QT1
L QTY PROBE 24QT1	L CADENSICON 19QT1 & L QTY PROBE 24QT1
L QTY PROBE 25QT1	L QTY PROBE 26QT1
L QTY PROBE 26QT1	L QTY PROBE 25QT1
L QTY PROBE 27QT1	L QTY PROBE 28QT1
L QTY PROBE 28QT1	L QTY PROBE 27QT1
L QTY PROBE 29QT1	L QTY PROBE 30QT1
L QTY PROBE 30QT1	L QTY PROBE 29QT1
L QTY PROBE 31QT1	L QTY PROBE 32QT1
L QTY PROBE 32QT1	L QTY PROBE 31QT1
L QTY PROBE 33QT1	L QTY PROBE 34QT1
L QTY PROBE 34QT1	L QTY PROBE 33QT1

2 RIGHT WING (PLUGS 4042VC-A AND 4044VC-A):

ORIGINAL PROBE MESSAGE	NEW MESSAGE AFTER PLUG CHANGE (SWAP)
R CADENSICON 19QT2	R QTY PROBE 24QT2
R QTY PROBE 21QT2	R QTY PROBE 22QT2
R QTY PROBE 22QT2	R QTY PROBE 21QT2
R QTY PROBE 23QT2	R QTY PROBE 24QT2
R QTY PROBE 24QT2	R CADENSICON 19QT2 & R QTY PROBE 24QT2
R QTY PROBE 25QT2	R QTY PROBE 26QT2
R QTY PROBE 26QT2	R QTY PROBE 25QT2
R QTY PROBE 27QT2	R QTY PROBE 28QT2
R QTY PROBE 28QT2	R QTY PROBE 27QT2
R QTY PROBE 29QT2	R QTY PROBE 30QT2
R QTY PROBE 30QT2	R QTY PROBE 29QT2
R QTY PROBE 31QT2	R QTY PROBE 32QT2
R QTY PROBE 32QT2	R QTY PROBE 31QT2
R QTY PROBE 33QT2	R QTY PROBE 34QT2
L QTY PROBE 34QT2	L QTY PROBE 33QT2

3 Open the C/Bs 1QT and 2QT.
4 Go to Para. 4.A.

4. Fault Isolation
Subtask 28-42-00-810-130-A ** ON A/C NOT FOR ALL

A. Procedure
(1) Remove the two connector plugs from the applicable aircraft wing AMM 28-42-43-000-008.

(2) Move the two connector plugs to a safe area. Example, an electrical workshop or an office space. This is because the area adjacent to a wing-tank can be a potentially explosive atmosphere.
(a) If you cannot obey step (2) you must use intrinsically safe versions of the types of test equipment given in step (3) (a), (b) and (c).
(3) Do a wiring test of the two fused connector plugs (internal wiring circuits) ASM 284205 ASM 284207 ( ASM 284206 ASM 284208) as follows:

NOTE: This is to make sure that only a unserviceable connector plug is replaced.

(a) Do a check for continuity ESPM 2052210, with a MULTIMETER - STANDARD, between the pin K and each of the pins that follow:

NOTE: Each of the (common drive return) wiring connections given in this step go through a fuse.

1 Make sure that there is continuity between each of the connections. Reject (as unserviceable) a connector that fails a part of this check.
(b) Do a check for continuity ESPM 2052210, with a multimeter, between the pin B and each of the pins that follow:

NOTE: Each of the (common drive) wiring connections given in this step are direct.

1 Make sure that there is continuity between each of the connections. Reject (as unserviceable) a connector that fails a part of this check.
(c) Do a check for insulation resistance ESPM 2052240, with a TESTER - INSULATION, 500 V, between the pins B and K. This is between the common drive and the common drive return wiring in the plug.
1 Make sure that the insulation resistance is more than 1 M ohm ESPM 2052240. This is sufficiently high to stop the drive and drive return from shorting out. Reject (as unserviceable) a connector that fails this check.
(4) Replace the applicable unserviceable:

fused connector plug 4041VC-A
( fused connector plug 4042VC-A )
fused connector plug 4043VC-A
( fused connector plug 4044VC-A ).

(5) Install the serviceable connector plugs in the aircraft AMM 28-42-43-400-008.
(6) Do the tests given in Para. 3. Fault Confirmation.

[Rev.8 from Aug 2018] 2026.04.04 04:39:49 UTC