DOC AIRBUS | AMM A320FWetting Current Procedure
TASK 36-22-00-200-802-A
Wetting Current Procedure
To supply wetting current to the OverHeat Detection System (OHDS) loops which have a higher Centre Wire Resistance (CWR) value than the maximum permitted CWR value specified in AMM procedure 36-22-00-760-802-A.
A wetting current is an electrical current that can go through the film oxidation or contamination at the surface of the connector contact mating-surfaces. The film oxidation or contamination can cause open fault messages in the OHDS loops. The supply of wetting current gives the location function more accurately.
This procedure can extend the operation of the OHDS loops less than 3 months or a longer time for the different OHDS loop locations and/or environmental conditions on the aircraft. Thus, it cannot be known for a specified time period.
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 36-22-00-860-075-A ** ON A/C NOT FOR ALL
Subtask 36-22-00-480-053-A ** ON A/C NOT FOR ALL
Subtask 36-22-00-410-061-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 01:16:37 UTC
Wetting Current Procedure
WARNING:
BEFORE YOU INSTALL/REMOVE THE GSE-TOOL, READ THE INSTRUCTIONS IN THE APPLICABLE GSE INSTRUCTION MANUAL. WHILE YOU OPERATE THIS TOOL, CAREFULLY OBEY THEM. IF YOU DO NOT OBEY THE INSTRUCTIONS, INJURY AND/OR DAMAGE CAN OCCUR.
1. Reason for the JobTo supply wetting current to the OverHeat Detection System (OHDS) loops which have a higher Centre Wire Resistance (CWR) value than the maximum permitted CWR value specified in AMM procedure 36-22-00-760-802-A.
A wetting current is an electrical current that can go through the film oxidation or contamination at the surface of the connector contact mating-surfaces. The film oxidation or contamination can cause open fault messages in the OHDS loops. The supply of wetting current gives the location function more accurately.
This procedure can extend the operation of the OHDS loops less than 3 months or a longer time for the different OHDS loop locations and/or environmental conditions on the aircraft. Thus, it cannot be known for a specified time period.
NOTE: This procedure is not applicable if there is a gold plate installed on the OHDS connecting-cable pins. The first three digits of the part numbers for the OHDS gold-plated connectors are 114.
2. Job Set-up InformationA. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| CB0X406 | 1 | CAPACITANCE DEC BOX |
| ELC132A | 1 | LCR METERS |
| HPG1 | 1 | SIGNAL GEN-POCKET |
| KRTG36-1032 | 1 | BLEED LOOP GROUND TEST |
| R5406 | 1 | CAPACITANCE DEC BOX |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 121 | AVIONICS COMPARTMENT |
| 122 | AVIONICS COMPARTMENT |
| 811 |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 24-41-00-861-002-A | Energize the Aircraft Electrical Circuits from the External Power |
| TASK 24-41-00-861-002-A-01 | Energize the Aircraft Electrical Circuits from the APU |
| TASK 24-41-00-861-002-A-02 | Energize the Aircraft Electrical Circuits from Engine 1(2) |
| TASK 24-41-00-862-002-A | De-energize the Aircraft Electrical Circuits Supplied from the External Power |
| TASK 24-41-00-862-002-A-01 | De-energize the Aircraft Electrical Circuits Supplied from the APU |
| TASK 24-41-00-862-002-A-02 | De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2) |
| TASK 36-11-34-000-001-A | Removal of the BMC |
| TASK 36-11-34-400-001-A | Installation of the BMC |
| TASK 36-22-00-100-803-A | Clean the Overheat Detection System (OHDS) Connectors and Apply the Electrical Insulating Compound |
| TASK 36-22-00-760-802-A | Measurement of the Centre Wire Resistance (CWR) of the OverHeat Detection System (OHDS) Loops |
| TASK 52-41-00-010-002-A | Open the Avionics Compartment Doors for Access |
| TASK 52-41-00-410-002-A | Close the Avionics Compartment Doors after Access |
Wetting Current ConnectionsSubtask 36-22-00-860-075-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
Subtask 36-22-00-865-078-A ** ON A/C NOT FOR ALL (1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
B. Open, safety and tag this(these) circuit breaker(s):
Subtask 36-22-00-010-059-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | AIR BLEED/ENG 2/MONG | 3HA2 | D12 |
| 49VU | AIR BLEED/ENG 1/CTL | 2HA1 | D11 |
| 122VU | AIR BLEED/ENG 1/MONG | 3HA1 | Z23 |
| 122VU | AIR BLEED/ENG 2/CTL | 2HA2 | Z22 |
C. Get access to the avionics compartment.
(1) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at access door 811.
(2) Open access door 811 to get access to the main avionics compartment (Ref. AMM TASK 52-41-00-010-002).
4. Procedure(1) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at access door 811.
(2) Open access door 811 to get access to the main avionics compartment (Ref. AMM TASK 52-41-00-010-002).
Subtask 36-22-00-480-053-A ** ON A/C NOT FOR ALL
A. Installation of the Tool
(1) Remove the Bleed Monitoring Computer (BMC) (1) that controls the loop on which you will do the procedure (Ref. AMM TASK 36-11-34-000-001).
(a) Make sure that all the switches are in the OUT position.
(b) Set the switches that follow to IN to select 10 µF:
(5) Connect the adapter (T3) to the top of the HPG1 SIGNAL GEN-POCKET (T1).
(6) Connect the test lead (T4) between the red plug of the adapter (T3) and the red plug of the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX (T2).
(7) Connect the banana plug of the test lead (T5) to the black plug of the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX(T2).
(8) Connect the banana plug of the test lead (T6) to the black plug of the adapter (T3).
(9) Start the HPG1 SIGNAL GEN-POCKET (T1).
(10) Make sure that the HPG1 SIGNAL GEN-POCKET (T1) battery is fully charged.
(a) Select a sine waveform.
(b) Select a frequency of 1 KHz.
(c) Select an amplitude of 8 V peak-to-peak (2.8 V RMS) output voltage.
Subtask 36-22-00-280-053-A ** ON A/C NOT FOR ALL (1) Remove the Bleed Monitoring Computer (BMC) (1) that controls the loop on which you will do the procedure (Ref. AMM TASK 36-11-34-000-001).
NOTE: BMC-1 controls zones loop A and loop APU. BMC-2 controls zone loop B.
(2) On the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX (T2): (a) Make sure that all the switches are in the OUT position.
(b) Set the switches that follow to IN to select 10 µF:
- 1 µF
- 2 µF
- 3 µF
- 4 µF.
NOTE: You can also use the KRTG36-1032 BLEED LOOP GROUND TEST as an alternative to the ELC132A LCR METERS.
(4) Use the ELC132A LCR METERS to make sure that the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX (T2) gives 10 µF (plus or minus 10 per cent). (5) Connect the adapter (T3) to the top of the HPG1 SIGNAL GEN-POCKET (T1).
(6) Connect the test lead (T4) between the red plug of the adapter (T3) and the red plug of the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX (T2).
(7) Connect the banana plug of the test lead (T5) to the black plug of the R5406 CAPACITANCE DEC BOX or CB0X406 CAPACITANCE DEC BOX(T2).
(8) Connect the banana plug of the test lead (T6) to the black plug of the adapter (T3).
(9) Start the HPG1 SIGNAL GEN-POCKET (T1).
(10) Make sure that the HPG1 SIGNAL GEN-POCKET (T1) battery is fully charged.
NOTE: After you use the HPG1 SIGNAL GEN-POCKET, we recommend that you charge the battery, refer to the manufacturer's instructions.
(11) In the HPG1 SIGNAL GEN-POCKET (T1) menu: (a) Select a sine waveform.
(b) Select a frequency of 1 KHz.
(c) Select an amplitude of 8 V peak-to-peak (2.8 V RMS) output voltage.
B. Wetting Current Procedure
(1) On the CWR table, do a check of the specified pins for the applicable loop.
(2) On the ELC132A LCR METERS, select the R series function and a frequency of 1 kHz.
(3) Measure the CWR in the loop between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(4) Make sure that the measured CWR value is stable.
(5) Record the measured CWR value.
(6) For loop start:
(a) Connect the end pin of the test lead (T5) to the applicable end pin given in the CWR table.
(b) Connect the end pin of the test lead (T6) to the applicable start pin given in the CWR table.
(c) Supply the wetting current during 60 seconds.
(d) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(7) For loop end:
(a) Connect the end pin of the test lead (T5) to the applicable start pin given in the CWR table.
(b) Connect the end pin of the test lead (T6) to the applicable end pin given in the CWR table.
(c) Supply the wetting current during 60 seconds.
(d) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(8) On the ELC132A LCR METERS, make sure that the R series function and a frequency of 1 kHz are selected.
(9) Measure the CWR of the applicable loop again between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(10) Compare the measured CWR value with the value that you recorded before.
(a) Make sure that the measured CWR value is lower than the maximum permitted CWR value for the loop.
(b) If the CWR value is not correct:
1 Clean the OHDS connectors and apply the electrical insulating compound (Ref. AMM TASK 36-22-00-100-803).
(11) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(12) Use the ELC132A LCR METERS to measure the CWR of the applicable loop again between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(13) Record the measured CWR value in the technical logbook.
(14) Install the BMC (1) (Ref. AMM TASK 36-11-34-400-001).
5. Close-up(1) On the CWR table, do a check of the specified pins for the applicable loop.
(2) On the ELC132A LCR METERS, select the R series function and a frequency of 1 kHz.
(3) Measure the CWR in the loop between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(4) Make sure that the measured CWR value is stable.
(5) Record the measured CWR value.
(6) For loop start:
(a) Connect the end pin of the test lead (T5) to the applicable end pin given in the CWR table.
(b) Connect the end pin of the test lead (T6) to the applicable start pin given in the CWR table.
(c) Supply the wetting current during 60 seconds.
(d) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(7) For loop end:
(a) Connect the end pin of the test lead (T5) to the applicable start pin given in the CWR table.
(b) Connect the end pin of the test lead (T6) to the applicable end pin given in the CWR table.
(c) Supply the wetting current during 60 seconds.
(d) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(8) On the ELC132A LCR METERS, make sure that the R series function and a frequency of 1 kHz are selected.
(9) Measure the CWR of the applicable loop again between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(10) Compare the measured CWR value with the value that you recorded before.
(a) Make sure that the measured CWR value is lower than the maximum permitted CWR value for the loop.
(b) If the CWR value is not correct:
1 Clean the OHDS connectors and apply the electrical insulating compound (Ref. AMM TASK 36-22-00-100-803).
(11) Disconnect the end pins of the test lead (T5) and the test lead (T6) from the connector.
(12) Use the ELC132A LCR METERS to measure the CWR of the applicable loop again between the start pin and the end pin (Ref. AMM TASK 36-22-00-760-802).
(13) Record the measured CWR value in the technical logbook.
(14) Install the BMC (1) (Ref. AMM TASK 36-11-34-400-001).
Subtask 36-22-00-410-061-A ** ON A/C NOT FOR ALL
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close access door 811 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).
Subtask 36-22-00-865-079-A ** ON A/C NOT FOR ALL (1) Make sure that the work area is clean and clear of tools and other items.
(2) Close access door 811 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).
B. Remove the safety clips and tags and close these circuit breakers in this sequence:
Subtask 36-22-00-860-076-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | AIR BLEED/ENG 2/MONG | 3HA2 | D12 |
| 49VU | AIR BLEED/ENG 1/CTL | 2HA1 | D11 |
| 122VU | AIR BLEED/ENG 1/MONG | 3HA1 | Z23 |
| 122VU | AIR BLEED/ENG 2/CTL | 2HA2 | Z22 |
C. Aircraft Maintenance Configuration
(1) Put the aircraft back to its initial configuration.
(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).
(1) Put the aircraft back to its initial configuration.
(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).