A Fuse In One Of The Left Wing-Tank Fused Connector Plugs Has Operated More Than One Time

TASK 28-42-00-810-880-A
A Fuse In One Of The Left Wing-Tank Fused Connector Plugs Has Operated More Than One Time

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

This procedure is not a full list of all the items (and LRUs) that can cause a fuse link in a left wing-tank fused connector plug to operate
It is a guide to logical troubleshooting to find the possible cause and emphasize some troubleshooting steps previously given

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

REFERENCE	QTY	DESIGNATION
No specific	AR	MULTIMETER - STANDARD

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 28-42-00-810-875-A	FQIs Degraded, Malfunction in a W/Tank when Fused Connector Plugs are Installed An Alternative Task for the Connector Plug Only and Caused by Moisture Ingress
ESPM 2031350
ESPM 2052210
ESPM 2053210
AMM 24-92-00-210-014	Inspection of the End Fittings of Electrical Conduits in the Main Landing Gear (MLG) Well and False Spar Box
AMM 28-42-00-740-001	Status Report (BITE)
ASM 284205
ASM 284207
AWM 940003

3. Fault Confirmation
Subtask 28-42-00-710-123-A ** ON A/C NOT FOR ALL

A. Test
(1) Not applicable.

4. Fault Isolation
Subtask 28-42-00-810-138-A ** ON A/C NOT FOR ALL

A. Procedure

NOTE: This procedure is not a full list of all the items (and LRUs) that can cause a fuse link in a left wing-tank fused connector plug to operate. It is a guide to logical troubleshooting to find the possible cause and emphasize some troubleshooting steps previously given .

(1) If the identification of the fuel-quantity probe to the fuse link that has operated:

is known, do step (3)
is not known, do step (2).

(2) Do the test that follows on the applicable fused connector plug.
(a) Do a check for continuity ESPM 2052210, with a MULTIMETER - STANDARD, between the pin K and each of the pins, that follow:

L, M, N, P, R, Y, Z, and <A.

(b) Make a record of the fused wiring link that shows an open circuit.
(c) Compare the record of your result with the Tables 1 and 2 that follow to get the identification of the related fuel-quantity probe.
1 Table 1 - Is applicable to a fused connector plug when installed in the FUSED CONNECTOR PLUG 4041VC-A position.

OPERATED FUSE LINK	RELATED FUEL-QUANTITY PROBE
K -- -- L	L CADENSICON 19QT1
K -- -- M	L QTY PROBE 33QT1
K -- -- N	L QTY PROBE 31QT1
K -- -- P	L QTY PROBE 29QT1
K -- -- R	L QTY PROBE 27QT1
K -- -- Y	L QTY PROBE 25QT1
K -- -- Z	L QTY PROBE 23QT1
K -- -- <A	L QTY PROBE 21QT1

NOTE: The FUSED CONNECTOR PLUG 4041VC-A is related to the:

main wire routing 1S left wing AWM 940003
pressure seal (feedthrough) 4015VP
connector 4039VC1-A ASM 284205
harness 13QT1 (inner cell)
connector 4045VC1-A (Rib15)
harness 15QT1 (outer cell)
left wing group A fuel-probes.

2 Table 2 - Is applicable to a fused connector plug when installed in the FUSED CONNECTOR PLUG 4043VC-A position.

OPERATED FUSE LINK	RELATED FUEL-QUANTITY PROBE
K -- -- L	L CIC 24QT1
K -- -- M	L QTY PROBE 34QT1
K -- -- N	L QTY PROBE 32QT1
K -- -- P	L QTY PROBE 30QT1
K -- -- R	L QTY PROBE 28QT1
K -- -- Y	L QTY PROBE 26QT1
K -- -- Z	L QTY PROBE 24QT1
K -- -- <A	L QTY PROBE 22QT1

NOTE: The FUSED CONNECTOR PLUG 4043VC-A is related to the:

main wire routing 2S left wing AWM 940003
pressure seal (feedthrough) 4017VP
connector 4040VC1-A ASM 284207
harness 14QT1 (inner cell)
connector 4046VC1-A (Rib15)
harness 16QT1 (outer cell)
left wing group B fuel-probes.

(d) Make a record of the identified fuel-quantity probe.
(3) Get the applicable TSM Task for the identified fuel-quantity probe.
(4) Read all of this step before you do more work. This is important if this is the second or subsequent time a fuse link (in the fused connector plug) has operated.
(a) Severe (Wet) Weather
1 Read the ESPM topic Severe Weather And Moisture Prone (SWAMP) areas on the aircraft ESPM 2031350
2 Read the TSM procedure (Ref. TSM TASK 28-42-00-810-875).
3 Read the AMM inspection task AMM 24-92-00-210-014.
(b) Visual Inspections
Good lighting must be used to do all the visual inspections.
(c) The Repairs (of unserviceable wiring and connectors)
The repair(s) must be fully done with reference to the applicable topic in the Electrical Standard Practices Manual (ESPM). After the repair is fully completed the applicable wiring test must be done again.
(d) The Fuel Condition
The fuel-tanks must contain a minimum of:

water
debris (unwanted material).

Water in the fuel can cause microbiological contamination. Make sure that all the Maintenance Planning Document (MPD) scheduled servicing tasks (related to water and microbiological contamination) have been correctly done.

Debris (unwanted material). It is a possibility that a metallic object can cause a short circuit between the two concentric tubes, or the terminals, of a fuel-probe. Example, a small piece of a single strand of wire from a multi-strand larger wire. A metallic object can stay in one location for a period of time and then start to move about in the fuel-tank and possibly cause a short circuit.
(5) Do the applicable TSM Task for the identified fuel-quantity probe. Make sure that all the steps given in the FQIS fault isolation task/procedure are fully done.
(6) If the fault continues:
(a) Investigate the possibility of an apparent unrelated fault (in a different system) in the same wing and at the same time.

NOTE: The aircraft cable routes for the FQIS are installed in conduit/harness assemblies which contain wires used for other aircraft systems. The in-line fused connector plugs are to prevent short circuit conditions that if continued can cause in-tank components to overheat with the risk of fire or explosion.

1 Troubleshoot the related fault symptom(s), if necessary.
a See step (8) for the procedure to follow to get a list of wires that are installed parallel for part of the route from the left wing (false spar box) and enter the aircraft fusalage at the pressure seal/feed thru 4015VP (1S LH) or 4017VP (2S LH).
(b) Investigate the possibility that work or a repair that has been done in adjacent wiring or system has caused damage and given this fault.
1 Troubleshoot the related fault symptom(s), if necessary.
(7) If the fault continues:
(a) Do a visual inspection and electrical aircraft wiring checks of the main wire routing as follows AWM 940003:

for fused connector 4041VC-A, between the connector 4039VC1-A and the FQIC rack connector 3QT-A, is electrical wiring route 1S (sensitive system 1)
for fused connector 4043VC-A, between the connector 4040VC1-A and the FQIC rack connector 3QT-A, is electrical wiring route 2S (sensitive system 2).

(b) If necessary, get the single aisle aircraft drawings that follow for more cable routing data:

G.A. Electrics Zone 574-674, Ref. D922 40019
Frontier-Wing TE/FUS Electrical, Ref. D924 40100.

NOTE: The drawings can be got from Airbus Online Services (AOLS).

(c) Repair (or replace) all the unserviceable wiring and connectors ESPM 2053210.
(d) Do a wiring test of the repaired (or replaced) wiring and connectors.
(e) Do a Status Report (BITE) (Test of the FQIS) AMM 28-42-00-740-001.
(8) Do a search of:

the Aircraft Wiring List (AWL) in the aircraft master wire list (Ref. AWL 91-90) for the wires related to (that pass through) the equipments 4015VP and 4017VP (hookup list).

OR, if available
the Dynamic Wiring option for the wires related to (that pass through) the equipments 4015VP and 4017VP.

NOTE: The wire identity is given by a four digit ATA code and a four digit number, an example of which follows.

WIRE IDENT	EQUIPMENT FIN
2612-4500	4015VP

[Rev.8 from Aug 2018] 2026.04.04 04:29:10 UTC