Flushing of the Yellow Hydraulic System of the Power Transfer Unit (PTU)

TASK 12-36-29-170-005-A
Flushing of the Yellow Hydraulic System of the Power Transfer Unit (PTU)

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

WARNING: DO NOT GET THE FLUID ON YOUR SKIN OR IN YOUR EYES. IF YOU DO:

FLUSH IT AWAY WITH CLEAN WATER
GET MEDICAL AID.

1. Reason for the Job
To flush the Yellow hydraulic system after a failure in that part of the PTU 1088GM.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	1	CONTAINER 5 L (1.32 USGAL)
No specific	1	LOCALLY MANUFACTURED - ADAPTER
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY BARRIER(S)
No specific	1	WARNING NOTICE(S)
ALT29000001	1	HYD GRND PWR UNIT3000

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
198CB

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-36-29-170-005-A	Flushing of the Yellow Hydraulic System of the Power Transfer Unit (PTU)
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 29-00-00-910-002-A	Safety Procedures of the Hydraulic System
TASK 29-10-00-863-002-A	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 29-13-45-610-001-A	Servicing of the HP-Filter
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs
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
Yellow Hydraulic System of the PTU 1088GM - Flushing Schematic

3. Job Set-up
Subtask 12-36-29-860-062-A

A. Aircraft Maintenance Configuration
(1) Obey the hydraulic safety procedures (Ref. AMM TASK 29-00-00-910-002).
(2) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).
(3) Depressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-001).
(4) De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

Subtask 12-36-29-010-088-A

B. Get Access
(1) Open the right MLG door (Ref. AMM TASK 32-12-00-010-001).
(2) Open the access door 198CB.

Subtask 12-36-29-860-063-A

C. Preparation for the Flushing Procedure
(1) Put the WARNING NOTICE(S) in position.
(2) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(3) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position at the Zone 148.
(4) Put a CONTAINER 5 L (1.32 USGAL) in position to collect the hydraulic fluid below:

the PTU 1088GM,
the LP manifold 3003GM.

(5) Disconnect the pressure line from the Yellow hydraulic system side of the PTU 1088GM.
(6) Disconnect the case drain line from the Yellow hydraulic system side of the PTU 1088GM.
(7) Disconnect the case drain line from the LP manifold 3003GM.
(8) Connect the pressure line and the case drain line together with a union.
(9) Put the ALT29000001 HYD GRND PWR UNIT3000 in position as necessary.

CAUTION: MAKE SURE THAT THE FLOW RATE AND THE SUPPLY PRESSURE ON THE GROUND HYDRAULIC CART ARE SET TO A MINIMUM.

(10) Connect the pressure hose of the ALT29000001 HYD GRND PWR UNIT3000 to the delivery connector of 3008GM with an LOCALLY MANUFACTURED - ADAPTER.
(11) Connect the return hose of the hydraulic power cart to the manifold end of the case-drain line with an LOCALLY MANUFACTURED - ADAPTER.
(12) Put the PLUG-BLANKING in each disconnected line end.

4. Procedure
Subtask 12-36-29-170-054-A

A. Flush the Yellow hydraulic system.
(1) Operate the hydraulic power cart for 20 s at 20 bar (290.0754 psi).
(2) Stop the hydraulic power cart.

Subtask 12-36-29-960-054-A

B. Replace the Filter Element
(1) Replace the Yellow HP filter element 3048GM (Ref. AMM TASK 29-13-45-610-001).
(2) Make sure that the clogging indicators on the filter 3048GM are in (the filter is not clogged).
(3) If the filter is clogged, repeat the flushing procedure of the Yellow hydraulic system of the PTU (Ref. AMM TASK 12-36-29-170-005).

5. Close-up
Subtask 12-36-29-860-064-A

A. Put the system back to the serviceable condition.
(1) Disconnect the return hose of the hydraulic power cart and the adaptor from the case drain line.
(2) Disconnect the pressure hose of the hydraulic power cart and the adaptor from the delivery connector 3008GM.
(3) Disconnect and remove the union from the pressure line and the case drain line.
(4) Remove the hydraulic power cart.
(5) Remove the blanking plugs.
(6) Connect the case drain line to the PTU 1088GM.
(7) Connect the pressure line to the PTU 1088GM.
(8) Connect the case drain line to the LP manifold 3003GM.

Subtask 12-36-29-790-054-A

B. Leak Test of the Components which were Disconnected
(1) Pressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002).
(2) Make sure that there is no hydraulic fluid leakage.
(3) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).

Subtask 12-36-29-942-093-A

C. Put the aircraft back to its initial configuration.
(1) Remove the container.
(2) Remove the safety barriers.
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

Subtask 12-36-29-410-075-A

D. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the right MLG door (Ref. AMM TASK 32-12-00-410-001).
(3) Close the access door 198CB.
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.03.31 22:58:29 UTC