DOC AIRBUS | TSM A320FLoss of the Correct Quantity in the Yellow Hydraulic Reservoir
TASK 29-13-00-810-801-A
Loss of the Correct Quantity in the Yellow Hydraulic Reservoir
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 29-13-00-865-050-A
Subtask 29-13-00-810-066-A
[Rev.8 from Aug 2018]
2026.04.04 04:29:24 UTC
Loss of the Correct Quantity in the Yellow Hydraulic Reservoir
1. Possible Causes
- LOW LEVEL SWITCH
- wiring
- QUANTITY INDICATOR - TRANSMITTER
- hydraulic lines
- SDAC-1 [1WV1]
- SDAC-2 [1WV2]
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 31-54-00-810-835-A | Loss of the YELLOW RSVR QTY Input of the SDAC 1 |
| TSM TASK 31-54-00-810-836-A | Loss of the YELLOW RSVR QTY Input of the SDAC 2 |
| AMM 24-41-00-861-002 | Energize the Aircraft Electrical Circuits from the External Power |
| AMM 29-00-00-280-003 | Check of the Internal Leakage of the Yellow Hydraulic System |
| AMM 29-00-00-280-006 | Check of the Green or Yellow Hydraulic System after Engine Pump Failure or Operation in a Possible Cavitation Condition - with Ground Cart Available |
| AMM 29-00-00-790-001 | Check of the External Leaks of the Hydraulic Components |
| ASM 291301 | |
| AMM 29-13-41-000-003 | Removal of the Quantity Indicator of the Yellow Hydraulic Reservoir |
| AMM 29-13-41-000-004 | Removal of the Low Level Switch of the Yellow Hydraulic Reservoir |
| AMM 29-13-41-400-003 | Installation of the Quantity Indicator of the Yellow Hydraulic Reservoir |
| AMM 29-13-41-400-004 | Installation of the Low Level Switch of the Yellow Hydraulic Reservoir |
| AMM 29-31-00-710-001 | Functional Check of Reservoir Low Level Warning |
| ASM 293101 | |
| ASM 293102 | |
| AMM 31-60-00-860-001 | EIS Start Procedure |
Subtask 29-13-00-865-050-A
A. Make sure that this(these) circuit breaker(s) is(are) closed:
Subtask 29-13-00-860-050-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 121VU | HYDRAULIC/LOW/LVL/IND | 1832GQ | N32 |
| 121VU | HYDRAULIC/HYD/QTY/IND | 1831GQ | P35 |
| 121VU | HYDRAULIC/G HYD/PUMP ENG1/MONG | 1702GK | R34 |
B. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(2) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(3) On the ECAM control panel on the center pedestal, push the HYD pushbutton switch. Make sure that the HYD page is shown on the system display of the ECAM.
(4) Look for fault indications on the upper ECAM DU, the lower ECAM DU and panel 40VU.
4. Fault Isolation(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(2) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(3) On the ECAM control panel on the center pedestal, push the HYD pushbutton switch. Make sure that the HYD page is shown on the system display of the ECAM.
(4) Look for fault indications on the upper ECAM DU, the lower ECAM DU and panel 40VU.
Subtask 29-13-00-810-066-A
A. If the Fault Confirmation gives:
-the message HYD Y RSVR LO LVL on the upper ECAM DU
-the contents indication (shows low-fluid level) on the lower ECAM DU in amber
-the PTU P/BSW FAULT light on panel 40VU
-the YELLOW ENG 2 PUMP P/BSW FAULT light on panel 40VU
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is more than or equal to 3.5 l (0.9246 USgal):
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
1 If the drain valve has a leak:
Subtask 29-13-00-810-067-A -the message HYD Y RSVR LO LVL on the upper ECAM DU
-the contents indication (shows low-fluid level) on the lower ECAM DU in amber
-the PTU P/BSW FAULT light on panel 40VU
-the YELLOW ENG 2 PUMP P/BSW FAULT light on panel 40VU
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is more than or equal to 3.5 l (0.9246 USgal):
- do a check for 28VDC between:
the LOW LEVEL SWITCH connector B/A and the connector B/C ASM 293102.
- do a check of the wiring between:
the LOW LEVEL SWITCH connector B/C and CB (1832GQ) and repair the wiring as necessary ASM 293102.
- replace the LOW LEVEL SWITCH AMM 29-13-41-000-004 and AMM 29-13-41-400-004.
- make sure that the wiring is not connected to GND between:
the LOW LEVEL SWITCH connector B/B and the DIODE (1156VD) connector 37 ASM 291301 and ASM 293102.
- repair the wiring as necessary.
- replace the QUANTITY INDICATOR - TRANSMITTER AMM 29-13-41-000-003 and AMM 29-13-41-400-003.
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
NOTE: A cavitation condition of the engine pump is possible when the engine pump operates with the engine pump fire-valve closed (if you set the ENG 1 (2) FIRE pushbutton on the Eng/APU fire panel), or with the reservoir below the low level (ECAM indication).
(b) Make sure that the drain valve of the hydraulic reservoir has no leaks. 1 If the drain valve has a leak:
- replace the drain valve.
- do a check of the hydraulic lines and the components for leaks AMM 29-00-00-790-001 and repair them.
- do a check of the internal leakage of the Yellow hydraulic system AMM 29-00-00-280-003.
- repair the defective component.
B. If the Fault Confirmation gives:
-the message HYD Y RSVR LO LVL on the upper ECAM DU
-the contents indication (shows low fluid level) on the lower ECAM DU in amber
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is more than or equal to 2.6 l (0.6868 USgal):
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
QUANTITY INDICATOR - TRANSMITTER connector A/D and connector A/E ASM 293101.
1 If there is no 26VAC:
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
LOW LEVEL SWITCH connector B/A and connector B/C ASM 293102.
1 If there is no 28VDC:
(a) If the drain valve has a leak:
Subtask 29-13-00-810-053-A -the message HYD Y RSVR LO LVL on the upper ECAM DU
-the contents indication (shows low fluid level) on the lower ECAM DU in amber
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is more than or equal to 2.6 l (0.6868 USgal):
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
NOTE: A cavitation condition of the engine pump is possible when the engine pump operates with the engine pump fire valve closed (if you set the ENG 1 (2) FIRE pushbutton on the Eng/APU fire panel), or with the reservoir below the low level (ECAM indication).
(b) Do a check for 26VAC between: QUANTITY INDICATOR - TRANSMITTER connector A/D and connector A/E ASM 293101.
1 If there is no 26VAC:
- do a check of the wiring between:
QUANTITY INDICATOR - TRANSMITTER connector A/D and CB (1831GQ) and repair the wiring as necessary ASM 293101.
- do a check for a ground signal between:
QUANTITY INDICATOR - TRANSMITTER connector A/E and ground ASM 293101.
- repair the wiring between QUANTITY INDICATOR - TRANSMITTER connector A/E and ground ASM 293101.
- replace the QUANTITY INDICATOR - TRANSMITTER AMM 29-13-41-000-003 and AMM 29-13-41-400-003.
- do the troubleshooting procedure for the loss of the YELLOW RSVR QTY input of the SDAC-1 [1WV1] (Ref. TSM TASK 31-54-00-810-835).
- do the troubleshooting procedure for the loss of the YELLOW RSVR QTY input of the SDAC-2 [1WV2] (Ref. TSM TASK 31-54-00-810-836).
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
NOTE: A cavitation condition of the engine pump is possible when the engine pump operates with the engine pump fire valve closed (if you set the ENG 1 (2) FIRE pushbutton on the Eng/APU fire panel), or with the reservoir below the low level (ECAM indication).
(b) Do a check for 28VDC between: LOW LEVEL SWITCH connector B/A and connector B/C ASM 293102.
1 If there is no 28VDC:
- do a check of the wiring between:
LOW LEVEL SWITCH connector B/C and CB (1832GQ) and repair the wiring as necessary ASM 293102.
- replace the LOW LEVEL SWITCH AMM 29-13-41-000-003 and AMM 29-13-41-400-003.
- make sure that the wiring is not connected to GND between:
LOW LEVEL SWITCH connector B/B and DIODE (1156VD) connector 37 ASM 291301 and ASM 293102.
- repair the wiring as necessary.
(a) If the drain valve has a leak:
- replace the drain valve.
- do a check of the hydraulic lines and components for leaks AMM 29-00-00-790-001 and repair them.
- do a check of the internal leakage of the Yellow hydraulic system AMM 29-00-00-280-003.
- repair the defective component.
C. If the Fault Confirmation gives:
-the message HYD Y RSVR LO LVL on the upper ECAM DU
-the PTU P/BSW FAULT on panel 40VU
-the YELLOW ENG 2 PUMP P/BSW FAULT on panel 40VU
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is less than 2.6 l (0.6868 USgal):
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
(2) Make sure that the drain valve of the hydraulic reservoir has no leaks.
(a) If the drain valve has a leak:
Subtask 29-13-00-710-053-A -the message HYD Y RSVR LO LVL on the upper ECAM DU
-the PTU P/BSW FAULT on panel 40VU
-the YELLOW ENG 2 PUMP P/BSW FAULT on panel 40VU
do a visual check of the quantity shown on the mechanical indicator of the Yellow reservoir.
(1) If the quantity shown is less than 2.6 l (0.6868 USgal):
(a) Do a check of the engine pump for a possible cavitation condition AMM 29-00-00-280-006.
NOTE: A cavitation condition of the engine pump is possible when the engine pump operates with the engine pump fire valve closed (if you set the ENG 1 (2) FIRE pushbutton on the Eng/APU fire panel), or with the reservoir below the low level (ECAM indication).
(b) Replace the QUANTITY INDICATOR - TRANSMITTER AMM 29-13-41-000-003 and AMM 29-13-41-400-003. (2) Make sure that the drain valve of the hydraulic reservoir has no leaks.
(a) If the drain valve has a leak:
- replace the drain valve.
- do a check of the hydraulic lines and the components for leaks AMM 29-00-00-790-001 and repair them.
- do a check of the internal leakage of the Yellow hydraulic system AMM 29-00-00-280-003.
- repair the defective component.
D. Do the operational test of the fluid low level warning AMM 29-31-00-710-001 to make sure that the operation is correct (no message shown).