W DOC AIRBUS | TSM A320F

Loss of the Yellow Reservoir Pressurization

TASK 29-13-00-810-803-A
Loss of the Yellow Reservoir Pressurization

1. Possible Causes
  • reservoir overfilling
  • AIR PRESSURE SWITCH [3384GH]
  • wiring
  • filter element
  • Y RSVR DEPRESS.VALVE [3087GM]
  • RELIEF-V.-Y.SYS. [3005GM]
  • GAUGE PRESSURE AIR [3383GM]
  • CHECK VALVE Y [3388GM]
  • OUTLET CHECK VALVE OF THE RESERVOIR PRESSURIZATION UNIT (P/N QA08325/QA08501)
  • BLEED AIR RESTICTOR [1392GM]
  • bleed air lines
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 29-14-00-810-801-A
Fault of the Hydraulic Reservoir Pressurizing System
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
ASM 291301
AMM 29-14-00-614-001
Depressurization of the Hydraulic Reservoirs
AMM 29-14-00-614-002
Pressurization of the Hydraulic Reservoirs through the Ground Connector
AMM 29-14-00-720-002
Functional Test of the Hydraulic Reservoir Pressurization System with the Left Engine
AMM 29-14-13-000-001
Removal of the Bleed-Air Line Restrictor
AMM 29-14-13-400-001
Installation of the Bleed-Air Line Restrictor
AMM 29-14-15-000-003
Removal of the Air Pressure Gage of the Yellow Hydraulic System
AMM 29-14-15-400-003
Installation of the Air Pressure Gage of the Yellow Hydraulic System
AMM 29-14-16-000-003
Removal of the Reservoir Depressurization Valve of the Yellow Hydraulic System
AMM 29-14-16-400-003
Installation of the Reservoir Depressurization Valve of the Yellow Hydraulic System
AMM 29-14-17-000-003
Removal of the Air Relief Valve of the Yellow Hydraulic System
AMM 29-14-17-400-003
Installation of the Air Relief Valve of the Yellow Hydraulic System
AMM 29-14-18-000-001
Removal of the Reservoir Pressure Check Valves
AMM 29-14-18-400-001
Installation of the Reservoir Pressure Check Valves
AMM 29-14-41-000-003
Removal of the Outlet Non-Return Valve of the Reservoir Pressurization Unit
AMM 29-14-41-400-003
Installation of the Outlet Non-Return Valve of the Reservoir Pressurization Unit
AMM 29-14-41-610-002
Servicing of the Reservoir Pressurization Filter
AMM 29-14-49-000-001
Removal of the Reservoir Pressurization Hose
AMM 29-14-49-400-001
Installation of the Reservoir Pressurization Hose
AMM 29-30-00-200-002
Check of the Reservoir Quantity Indication on the ECAM Display Unit
AMM 29-34-00-710-001
Operational Test of Reservoir Low Air Pressure Warning
AMM 29-34-11-000-003
Removal of the Reservoir Pressure Switch of the Yellow Hydraulic System
AMM 29-34-11-400-003
Installation of the Reservoir Pressure Switch of the Yellow Hydraulic System
AMM 31-60-00-860-001
EIS Start Procedure
F Reservoir Pressurization Connection
3. Fault Confirmation
Subtask 29-13-00-865-051-A
A. Make sure that this(these) circuit breaker(s) is(are) closed:
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUHYDRAULIC/Y HYD/PUMP ENG2/MONG3700GDQ37
Subtask 29-13-00-860-051-A
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 the panel 40VU.
   (5) Do a check for the reservoir overfilling on the ECAM DU AMM 29-30-00-200-002.
4. Fault Isolation
Subtask 29-13-00-810-050-B
A. If the fault confirmation gives:
  • The message HYD Y RSVR LO AIR PRESS on the upper ECAM DU
  • The message LO AIR PRESS on the lower ECAM DU
  • The PTU P/BSW FAULT on panel 40VU
  • The YELLOW ENG 1 PUMP P/BSW FAULT on panel 40VU.

   (1) Do a visual check of the pressure shown on the gage of the Yellow reservoir.
   (2) If the pressure is more than 25 psi (1.7237 bar):
  • Do a check for continuity of the wiring between the AIR PRESSURE SWITCH [3384GH] connector A/A and the AIR PRESSURE SWITCH [3384GH] connector A/C ASM 291301.
     (a) If there is continuity:
     (b) If there is no continuity:
  • Make sure that the wiring is not connected to GND between the AIR PRESSURE SWITCH [3384GH] connector A/C and the DIODE (1156VD) connector 39 ASM 291301.
       1 If the wiring is connected to GND:
  • Repair the wiring.
   (3) If the pressure shown on the gage of the Yellow reservoir is less than 25 psi (1.7237 bar):
  • Do a check of the clogging indicator on the reservoir pressurization unit (1360GM).
     (a) If the clogging indicator is out:
     (b) If the clogging indicator is not out, or the fault continues after the replacement of the filter element:
  • Pressurize the hydraulic reservoirs with a ground cart AMM 29-14-00-614-002
  • Do a check of the pressure drop on the gage of the hydraulic reservoir.
NOTE: No pressure drop is permitted in 15 minutes at a gage pressure of 50 psi (3.4474 bar)
       1 If the air pressure drop is not in the limits:
  • Do a check of the Y RSVR DEPRESS.VALVE [3087GM] for leaks.
         a If the Y RSVR DEPRESS.VALVE [3087GM] has a leak:
         b If the Y RSVR DEPRESS.VALVE [3087GM] has no leak:
  • Do a check of the RELIEF-V.-Y.SYS. [3005GM] for leaks.
         c If the RELIEF-V.-Y.SYS. [3005GM] has a leak:
         d If the RELIEF-V.-Y.SYS. [3005GM] has no leak:
  • Do a check of the GAUGE PRESSURE AIR [3383GM] for leaks.
         e If the GAUGE PRESSURE AIR [3383GM] has a leak:
         f If the GAUGE PRESSURE AIR [3383GM] has no leak:
  • Do a check of all the connections and components on the reservoir for leaks.
         g If you find a leak:
  • Tighten the related nut or replace the defective component.
         h If the fault continues:
         i If the fault continues:
       2 If the air pressure drop is in the limits:
         a Depressurize the hydraulic reservoirs AMM 29-14-00-614-001.
         b Pressurize the reservoir pressurization system with the left engine AMM 29-14-00-720-002, or
         c Connect an external pressure source:
F Reservoir Pressurization Connection
  • Disconnect the reservoir pressurization hose (1674GM) (1) from the HP bleed-air port (3) of the left engine AMM 29-14-49-000-001.
  • Put a blanking plug on the HP bleed-air port (3).
  • Install the union (6) at the line end fitting (5) of an approved air or nitrogen source.
  • Make sure that the open end of the union (6) has a thread of 7/16_20UNJF 3A.
  • Connect the line end fitting (2) of the reservoir pressurization hose (1) (1674GM) to the thread 7/16_20UNJF 3A of the union (6).
  • Pressurize the reservoir pressurization system to approximately 15.2 bar (220 psi).
         d If the pressure in the reservoir does not increase to the necessary value:
         e If the fault continues:
  • Do a check and, if necessary, repair the bleed air line in the left pylon to the reservoir pressurization unit (1360GM).
         f If the fault continues:
  • Do a check and, if necessary, repair the remaining bleed air lines and components.
         g Stop the pressurization of the reservoir pressurization system from the left engine AMM 29-14-00-720-002, or
         h Disconnect the external pressure source:
  • Disconnect the line end fitting (2) of the reservoir pressurization hose (1) (1674GM) from the union (6).
  • Remove the union (6) from the line end fitting (5) of the pressure source hose (4).
  • Remove the blanking plug from the HP bleed-air port (3).
  • Connect the reservoir pressurization hose (1) (1674GM) to the HP bleed-air port (3) of the left engine AMM 29-14-49-400-001.
         i If the air pressure in the reservoir increases to the necessary value and the air pressure drop is in the limits:
  • No further actions are necessary.
   (4) Do the fault isolation procedure (Ref. TSM TASK 29-14-00-810-801).
Subtask 29-13-00-710-054-A
B. Do the operational test of the low air pressure warning AMM 29-34-00-710-001 to make sure that operation is correct (no maintenance message shown).
[Rev.8 from Aug 2018] 2026.04.04 04:39:57 UTC
"AVIABRAIN" 2025