Depressurize the Yellow Hydraulic System

TASK 29-10-00-864-002-A
Depressurize the Yellow Hydraulic System

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

1. Reason for the Job
To make sure that the Yellow hydraulic system is depressurized before work is done on the system.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Referenced Information

REFERENCE	DESIGNATION
TASK 29-23-00-860-001-A	Disconnection of the Isolation Coupling of the Power Transfer Unit (PTU)
TASK 29-23-00-860-002-A	Connection of the Isolation Coupling of the Power Transfer Unit (PTU)
TASK 31-60-00-860-001-A	EIS Start Procedure
TASK 31-60-00-860-002-A	EIS Stop Procedure
TASK 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 32-12-00-410-001-A	Close the Main Gear Doors after Access

3. Job Set-up
Subtask 29-10-00-860-052-A

A. Aircraft Maintenance Configuration
(1) Stop the supply of hydraulic power to the Yellow and Green hydraulic systems through the ground connections.
(2) If the Yellow electric pump is in operation:

in the flight compartment (on section 40VU of the overhead panel) push and release the YELLOW ELEC PUMP pushbutton switch.

(3) Make sure that the ON legend goes off.
(4) Open one of the main doors of the main landing gear (Ref. AMM TASK 32-12-00-010-001).

NOTE: You can open the left door or the right door, but access is better from the right side.

(5) Disconnect the PTU isolation coupling (Ref. AMM TASK 29-23-00-860-001).

NOTE: If necessary, you can now pressurize the Green hydraulic system.

(6) Do the EIS start procedure (upper ECAM DU and lower ECAM DU only)
(Ref. AMM TASK 31-60-00-860-001).
(7) On the ECAM control panel on the center pedestal, push the HYD pushbutton switch (P/BSW) . Make sure that the lower (system) display shows the HYD page.

Subtask 29-10-00-865-053-A

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N31
** ON A/C ALL
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

4. Procedure
Subtask 29-10-00-864-050-B ** ON A/C NOT FOR ALL

A. Depressurization

NOTE: When the hydraulic pressure supply stops, the pressure decreases quickly to approximately 700 psi / 50 bar. From this value the pressure decreases very slowly to zero (approximately 15 minutes).

(1) Refer to the ECAM indication of the YELLOW system pressure and make sure it shows 0.

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(2) If the ECAM indication of the YELLOW system pressure does not show 0, operate the rudder to reduce the pressure to zero.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

(3) If you will work on the auxiliary/parking brake systems:
(a) Operate the manual depressurization button on the brake relief valve 3067GM to release the pressure.
(b) On panel 110VU of the center pedestal, operate the PARKING BRK switch and refer to the triple gage on panel 400VU.
(c) Set the PARKING BRK switch to ON.
(d) Make sure that the triple gage shows zero pressure on all three indicators.

Subtask 29-10-00-864-050-C ** ON A/C NOT FOR ALL

A. Depressurization

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Refer to the ECAM indication of the YELLOW system pressure and make sure that it shows 0.
(2) If the ECAM indication of the YELLOW system pressure does not show 0, operate the rudder to reduce the pressure to zero.
(3) If you will work on the auxiliary/parking brake systems:

(a) Set the Anti-Skid and Nose Wheel switch to OFF.
(b) Operate the manual depressurization button on the brake relief valve 3067GM to release the pressure.
(c) Set the PARKING BRK switch to ON.
(d) Make sure that the triple gage shows zero pressure on all three indicators.

5. Close-up
Subtask 29-10-00-865-050-A

A. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N31
** ON A/C ALL
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

Subtask 29-10-00-860-053-A

B. Put the aircraft back to the serviceable condition.
(1) Connect the PTU isolation coupling (Ref. AMM TASK 29-23-00-860-002).
(2) Close the main door of the main landing gear (Ref. AMM TASK 32-12-00-410-001).
(3) Do the EIS stop procedure
(Ref. AMM TASK 31-60-00-860-002).

[Rev.10 from 2021] 2026.04.01 00:13:39 UTC