Functional Check of the Brake Accumulator System with the Parking Brake Applied

TASK 32-45-00-720-002-A
Functional Check of the Brake Accumulator System with the Parking Brake Applied

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.

WARNING: MAKE SURE THAT THE CONTROLS AGREE WITH THE POSITION OF THE ITEMS THEY OPERATE BEFORE YOU PRESSURIZE A HYDRAULIC SYSTEM. UNWANTED MOVEMENT OF HYDRAULICALLY OPERATED ITEMS CAN CAUSE SERIOUS INJURY AND/OR DAMAGE.

WARNING: PRESSURIZE ONLY THE HYDRAULIC SYSTEM(S) THAT IS (ARE) NECESSARY FOR THE TASK. ISOLATE THE OTHER HYDRAULIC SYSTEM(S) BEFORE YOU SUPPLY HYDRAULIC POWER TO THE AIRCRAFT.

WARNING: MAKE SURE THAT ALL THE CIRCUITS IN MAINTENANCE ARE ISOLATED BEFORE YOU SUPPLY ELECTRICAL POWER TO THE AIRCRAFT. UNWANTED ELECTRICAL POWER CAN BE DANGEROUS.

ZONE: 190
ZONE: 210
ZONE: 730
ZONE: 740

1. Reason for the Job
Refer to the MPD TASK: 324500-02
FUNCTIONAL CHECK OF BRAKE ACCUMULATOR SYSTEM WITH THE PARKING BRAKE APPLIED
To do a leakage test of the Brake Accumulator System.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
190	BELLY FAIR, AIR CONDITIONING & HYD COMPT
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
730	LEFT MAIN LANDING GEAR & DOORS
740	RIGHT MAIN LANDING GEAR & DOORS

C. Referenced Information

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 29-10-00-864-001-A	Depressurize the Green Hydraulic System
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 32-44-11-200-001-A	Functional Check of Parking/Emergency Brake Accumulator by Reading the Charge Pressure on the Accumulator Gauge

3. Job Set-up
Subtask 32-45-00-865-051-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	L/G/Y BRK/PRESS/IND	61GG	C10
** ON A/C NOT FOR ALL
49VU	ABCU &/Y BRK/PRESS IND	61GG	C10
** 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

Subtask 32-45-00-860-053-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) On panel 400VU, make sure that the landing-gear control lever is in the DOWN position.
(2) On panel 110VU, make sure that the PARKING BRK control-switch is in the OFF position.
(3) Make sure that the CAPT and F/O brake pedals are released.
(4) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(5) Make sure that the Green and Yellow hydraulic systems are depressurized
(Ref. AMM TASK 29-10-00-864-001) and (Ref. AMM TASK 29-10-00-864-002).
(6) Do the check of the brake accumulator nitrogen charging pressure (Ref. AMM TASK 32-44-11-200-001).
(7) On panel 110VU, put the PARKING BRK control-switch to the ON position.
(8) On overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend comes on) to pressurize the brake accumulator system to its nominal pressure 206 bar (2988 psi).
(a) Make sure that the brake accumulator pressure shown on the ACCU PRESS indication on triple pressure indicator 60GG, on panel 400VU is within the green band.
(9) On overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend goes off).

Subtask 32-45-00-860-053-B ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) On panel 400VU, make sure that the landing-gear control lever is in the DOWN position.
(2) On panel 110VU, make sure that the PARKING BRK control-switch is in the OFF position.
(3) Make sure that the CAPT and F/O brake pedals are released.
(4) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(5) Make sure that the Green and Yellow hydraulic systems are depressurized
(Ref. AMM TASK 29-10-00-864-001) and (Ref. AMM TASK 29-10-00-864-002).
(6) Do the check of the brake accumulator nitrogen charging pressure (Ref. AMM TASK 32-44-11-200-001).
(7) On panel 110VU, put the PARKING BRK control-switch to the ON position.
(8) On overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend comes on) to pressurize the brake accumulator system to its nominal pressure 206 bar (2988 psi).
(a) Make sure that the brake accumulator pressure shown on the ACCU PRESS indication on triple pressure indicator 60GG, on panel 400VU is within the green band.
(9) On the overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend goes off).

Subtask 32-45-00-860-053-C ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) On panel 400VU, make sure that the landing-gear control lever is in the DOWN position.
(2) On panel 110VU, make sure that the PARKING BRK control-switch is in the OFF position.
(3) Make sure that the CAPT and F/O brake pedals are released.
(4) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(5) Make sure that the Green and Yellow hydraulic systems are depressurized
(Ref. AMM TASK 29-10-00-864-001) and (Ref. AMM TASK 29-10-00-864-002).
(6) Do the check of the brake accumulator nitrogen charging pressure (Ref. AMM TASK 32-44-11-200-001).
(7) On panel 110VU, put the PARKING BRK control-switch to the ON position.
(8) On overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend comes on) to pressurize the brake accumulator system to its nominal pressure 206 bar (2988 psi).
(a) Make sure that the brake accumulator pressure shown on the ACCU PRESS indication on triple pressure indicator 60GG, on panel 400VU is within green band.
(9) On the overhead panel 40VU, push and release the YELLOW/ELEC PUMP pushbutton switch (ON legend goes off).

Subtask 32-45-00-941-051-A

C. Safety Precautions
(1) Put the WARNING NOTICE(S) in position to tell the persons not to:

operate the landing gear control lever,
operate the brake pedals,
operate the parking brake lever.

(2) Put the WARNING NOTICE(S) in position to tell the persons not to pressurize the Green and Yellow hydraulic systems:

On panel 40VU in the cockpit,
On access door 197CB, on the ground service panel of the Green hydraulic system,
On access door 198CB, on the ground service panel of the Yellow hydraulic system.

4. Procedure
Subtask 32-45-00-720-050-A

A. Do this test:
(1) On the accumulator pressure gage make sure that the accumulator pressure is not lower than that shown in the table below:

PARKING BRAKE ON (HOURS)	0	1	2	3	4	5	6	12
ACCU PRESSURE BARS (PSI)	206 (2988)	180 (2611)	167 (2422)	160 (2321)	153 (2219)	149 (2161)	145 (2103)	100 (1450)

NOTE: We recommend that you do the test at an ambient temperature near 20 deg.C (68.00 deg.F).

(2) If after 3 hours, the pressure drop is in the tolerance you can stop the test and no maintenance action is necessary.
(a) If the test results are not satisfactory, continue the test for the full 12 hours.
(3) If the pressure drop is out of tolerance, do the check of the system to find the leak.

Subtask 32-45-00-860-052-A

B. Aircraft Maintenance Configuration
(1) De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

5. Close-up
Subtask 32-45-00-942-050-A

A. Removal of Equipment
(1) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 00:49:53 UTC