General Rules for Removal and Installation Procedures in the Hydraulic Systems

TASK 29-00-00-910-004-A
General Rules for Removal and Installation Procedures in the Hydraulic Systems

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.

WARNING: MAKE SURE THAT THE HYDRAULIC SYSTEM(S) IN MAINTENANCE IS(ARE) ISOLATED BEFORE YOU PRESSURIZE THE OTHER HYDRAULIC SYSTEM(S).

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	CAP - BLANKING
No specific	1	CONTAINER - HYDRAULIC FLUID RESISTANT
No specific	AR	PLUG - BLANKING
No specific	1	SCRAPER - NON METALLIC

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.02ABA1)	Phosphate Ester Hydraulic Fluid-General Power - -
(Material No.04QAB2)	Coating_- Flexible Structure
(Material No.06AAA1)	Polysulfide Sealant_General Purpose Brushable -
(Material No.14DBB1)	Release Agent-- Liquid Wax -

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-12-29-611-001-A	Fill the Hydraulic Fluid Reservoir with a Hand Pump
TASK 12-12-29-611-002-A	Fill the Hydraulic Fluid Reservoir with a Hydraulic Service Cart
TASK 20-21-12-911-001-A	Tightening Torques for Pipe Unions (not for OXYGEN Unions)
TASK 20-23-11-917-001-A	Tightening Practices for Hydraulic Connections
TASK 20-23-21-911-001-A	Removal/Installation of the Bobbins from their Housings and Installation of O-rings, Square Seals, and Back-up Rings on the Bobbins
TASK 20-23-22-910-001-A	Marking of the Unions after Application of Standard or Specific Tightening Torque
TASK 20-29-00-911-002-A	Removal/Installation of an O-ring (Hydraulic Systems)
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 29-00-00-870-001-A	Bleeding Procedure of the Green Hydraulic System Upstream of the Engine Pump
TASK 29-00-00-870-002-A	Bleeding Procedure of the Green Hydraulic System Upstream of the PTU
TASK 29-00-00-870-003-A	Bleeding Procedure of the Green Hydraulic System Downstream of the Engine Pump
TASK 29-00-00-870-004-A	Bleeding Procedure of the Yellow Hydraulic System Upstream of the Engine Pump
TASK 29-00-00-870-005-A	Bleeding Procedure of the Yellow Hydraulic System Upstream of the PTU
TASK 29-00-00-870-006-A	Bleeding Procedure of the Yellow Hydraulic System Upstream of the Yellow E-Pump
TASK 29-00-00-870-007-A	Bleeding Procedure of the Yellow Hydraulic System Downstream of the Engine Pump
TASK 29-00-00-870-008-A	Bleeding Procedure of the Blue Hydraulic System Upstream of the Blue E-Pump
TASK 29-00-00-870-009-A	Bleeding Procedure of the Blue Hydraulic System Downstream of the Blue E-Pump
TASK 29-00-00-910-002-A	Safety Procedures of the Hydraulic System
TASK 29-10-00-863-001-A	Pressurize the Green Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-002-A	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-003-A	Pressurize the Blue Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-003-A-01	Pressurize the Blue Hydraulic System with the Blue Electric Pump
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs
TASK 29-14-00-614-002-A	Pressurization of the Hydraulic Reservoirs through the Ground Connector
TASK 29-14-00-614-002-A-01	Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU)
TASK 29-23-00-863-001-A	Pressurize the Green Hydraulic System from the Yellow Hydraulic System through the PTU with the Electric Pump
Example for a Hydraulic Bulkhead Fitting Installation

3. Job Set-up
Subtask 29-00-00-910-057-A

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

A. Aircraft Maintenance Configuration

NOTE: AIRBUS recommend that you do not work on all three hydraulic systems during the same maintenance input with the same maintenance personnel.
This is to make sure that a possible maintenance error on one system is not done again on a different system.
A maintenance error on more than one hydraulic system can cause system failure on multiple systems. If maintenance is necessary on more than one system at the same time and involves lines/components disconnection, different maintenance personnel must be used for each system.
If maintenance needs to be performed on all three hydraulic systems at the same time a special check by a third person shall be performed to verify proper bleeding, torques and locking of bolts and nuts have been applied, this is in addition to the leak check of the pressurized system.
Regarding hydraulic system bleeding, this could be carried out by means of a hydraulic ground cart.
Engine run is requested if maintenance action has been done on hydraulic system located on the engine area.

(1) Obey the hydraulic safety procedures (Ref. AMM TASK 29-00-00-910-002).
(2) Make sure that the related hydraulic system is depressurized and put it in the maintenance configuration (Ref. AMM TASK 29-00-00-864-001).
(3) Depressurize the reservoir of the related hydraulic system (Ref. AMM TASK 29-14-00-614-001).
(4) Put a CONTAINER - HYDRAULIC FLUID RESISTANT below the hydraulic connections to collect the unwanted fluid.

4. Procedure
Subtask 29-00-00-910-059-A

A. General Instructions
(1) Do a local check in the work area where you do the maintenance operations to see if the preventive maintenance actions are possible.
(2) When you do a maintenance action on one (some) component(s) in the same area, clean the adjacent area.
(3) You must do a careful final check (see Para G. (1)) when the operations are completed and before the doors or access panels are closed.
(4) Persons who do the maintenance on the hydraulic system must read and obey the safety precautions.
(5) The system will stay functional and safe if you fully obey the instructions.
(6) Skin can become dry and chapping can occur if you touch the hydraulic fluid for a long time.

Subtask 29-00-00-960-051-A

B. Replacement of a Component
(1) When you install parts from the removed component on the replacement component, do this:
(a) Always write the position and the angle of the fittings that you remove from the components. This will help you to install and align them correctly on the replacement component.
(b) Clean the removed part and do a check for serviceable condition.
(c) When you clean metal parts before assembly, only use solvent (Material No. 11-003 or 11-006). Make sure that there is no solvent on the parts before assembly.
(d) To flush the hydraulic components or do a test on them, only use approved hydraulic fluids.
(e) Replace all seals and safety devices. Keep O-rings and seals for the hydraulic system in their containers until you install them.
(f) When you install O-rings refer to (Ref. AMM TASK 20-29-00-911-002).
(g) When you assemble O-rings and seals for the hydraulic system, only use approved lubricant or hydraulic fluid. Always lubricate O-rings and seals immediately before installation.
(h) When you install or remove bobbins from components, refer to (Ref. AMM TASK 20-23-21-911-001).
(i) When you remove check-valves from components, remove the related hydraulic pipes.
(j) When you remove a component, make sure that:

The system is depressurized (Ref. AMM TASK 29-00-00-864-001).
The reservoir is depressurized (Ref. AMM TASK 29-14-00-614-001).

(k) When you install a component, make sure that it is in the same position and aligned as it was before.
(l) During the test, make sure that parts from a removed component operate correctly.

Subtask 29-00-00-960-050-A

C. Replacement of Hydraulic Bulkhead Fittings

(1) Remove the bulkhead fitting:

CAUTION: USE A SECOND WRENCH TO APPLY COUNTERTORQUE TO THE UNION WHEN YOU DISCONNECT/CONNECT HYDRAULIC LINES ON UNIONS. IF YOU DO NOT USE THE SECOND WRENCH, THERE IS A RISK THAT YOU WILL LOOSEN OR TIGHTEN THE UNION TOO MUCH.

(a) Loosen the union nuts and disconnect the pipes from the bulkhead fitting.
(b) Install the PLUG - BLANKING in the union nuts.
(c) Disconnect the locknut and the washer (if installed) from the bulkhead fitting.
(d) Remove the bulkhead fitting from the bulkhead.
(e) Install the CAP - BLANKING on the bulkhead fitting.
(2) Install the bulkhead fitting:
(a) Clean the component interfaces and the adjacent area.
(b) If necessary, remove the old sealant with a SCRAPER - NON METALLIC from the bulkhead fitting and from the bulkhead.
(c) Do an inspection of the component interfaces and the adjacent area.
(d) Make sure that there is no:

Corrosion
Deformation
Or any other damage
in the installation area.

(e) Make sure that the hydraulic line end-fittings are serviceable.
(f) Apply the material (1) release agent Release Agent-- Liquid Wax - (Material No.14DBB1) or a separating foil on the bulkhead.
(g) Apply the material (2) Polysulfide Sealant_General Purpose Brushable - (Material No.06AAA1) under the nut of the bulkhead fitting and the washer (if installed).
(h) Remove the blanking caps from the bulkhead fitting.
(i) Install the bulkhead fitting in the bulkhead with the washer (if installed) and the locknut.

(j) TORQUE the locknut to the correct torque value (Ref. AMM TASK 20-21-12-911-001).
(k) Apply the Phosphate Ester Hydraulic Fluid-General Power - - (Material No.02ABA1) to the threads of the bulkhead fittings.
(l) Remove the blanking plugs from the union nuts.
(m) Connect the union nuts with the bulkhead fitting.
(n) TORQUE the union nuts to the correct torque value (Ref. AMM TASK 20-21-12-911-001).
(o) Let the sealant dry.
(p) Apply the material (3) Coating_- Flexible Structure (Material No.04QAB2) on the sealant layer.

Subtask 29-00-00-870-069-A

D. General Bleeding Procedure for the Hydraulic System

CAUTION: BLEED THE RELATED HYDRAULIC SYSTEMS AFTER THE INSTALLATION OF LINES OR COMPONENTS (FILTER ELEMENTS INCLUDED) ON THE PRESSURE SIDE OF THE SYSTEM. THIS IS TO MAKE SURE THAT THERE IS NO AIR/GAS IN THE SYSTEM.

(1) Make sure that the level of the fluid in the reservoir of the applicable hydraulic system is correct. Add fluid as necessary:

(2) Pressurize the reservoir of the applicable hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(3) Pressurize the applicable hydraulic system:

(4) Make sure that there are no hydraulic leaks.
(5) Do the applicable bleeding procedure:

Subtask 29-00-00-110-050-A

E. Cleaning
(1) Put blanking caps on the electrical connectors (wiring, components), pipes and components when you disconnect or remove them.
(2) Remove all items which are not necessary in the work area: tools, pieces of lockwire, plastic clamps, cloths and unwanted material.
(3) Apply a sheet of vinyl on the lubricated parts of the mechanical linkages.
(4) Carefully remove liquid which spilled (fluid, fuel, water and others).
(5) Clean the area with solvent and dry the applicable area with lint free cloth.
(6) Dry with compressed air if necessary.

Subtask 29-00-00-220-051-A

F. Check
(1) Lines and ducts:
(a) When the lines are disconnected and/or components removed:

Install blanking caps or covers so that unwanted material does not go into the lines or components.

(b) Hoses:
1 Make sure that hose identification placards are installed and that they are in serviceable condition.
2 Do a check of the clamps, make sure that:
Make sure that:

Their diameter is correct before they are installed
Their condition is satisfactory
Their installation is correct.

3 Make sure that there are no signs of wear on the hoses caused by friction, vibrations and pressure surges.
4 Make sure that:

The positions of the hoses are correct
There is no friction with other lines, bulkheads or components
The hoses are not twisted and have no cracks.

5 Lightly bend the hoses in the center to make sure that they move freely.
6 Make sure that there is no fluid leaks at the hose unions.
7 Make sure that the safety devices are in a satisfactory condition and that they are correctly installed.
(c) Pipes:
1 Specially at the elbows and pipe-to-component fittings, make sure that:

They are not damaged
There are no cracks

2 Make sure that the metal parts, clamps or bolts do not cause damage to the pipes.
3 Make sure that there are no leaks at the fittings and that the safety devices are in a satisfactory condition and correctly installed.
4 Make sure that the supports, clamp blocks and clamps are correctly tightened and are in a serviceable condition.
(2) Wiring, connectors and components:
(a) When the electrical connectors are disconnected, install blanking caps to prevent damage to the pins and sockets.
(b) Wiring:
1 Do a visual check of the external condition of the wiring (insulation, shielding, conduit).
2 Make sure there is no hydraulic fluid on the coaxial cables.
3 Make sure that the clips and fittings that attach the cable bundles to the structure are correctly installed.
4 Make sure that the adjacent components are attached correctly, so that they do not touch the wiring or cable bundles.
(c) Connectors/components:
1 Make sure that the electrical connectors are in satisfactory condition and are correctly installed. Make sure that there is no contamination from fluid leaks.
2 Make sure that the attach fittings and safety devices are in correct condition.
3 Do a check of the safety devices.
4 Make sure that there are no fluid leaks in the areas where hydraulic equipment is installed.
5 For the components with an electrical power supply, make sure that the connectors are correctly safetied.
6 Do a check of the condition of the fork and eye joints on the mechanically-operated components.
(3) Bonding:
(a) Make sure that the bonding jumpers are installed, are in the correct condition and are correctly safetied.
(b) Make sure that each component, control linkage part, control surface or hinged part is electrically connected to the structure through bonding jumpers or connections.
(c) Make sure that there is lacquer on the bonding connections and that there is no sign of corrosion.
(4) Safety devices:
(a) Make sure that all safety devices are correctly installed.
(b) Make sure that the cotter pins are correctly installed through the castellated nuts.
(c) Make sure that lockwire is installed where necessary and that the tension and direction of pull are correct.
(d) Make sure that the tabs of the tab washers are correctly folded back.
(e) Make sure that color marks on the nuts are aligned with the marks on the structure.

Subtask 29-00-00-210-058-A

G. Final Check
(1) Before you close the access doors:
(a) Make sure that the work area is clean and clear of unwanted grease, sealant, pieces of lockwire, plastic clips, cloths and other unwanted material.
(b) Make sure that the work area is clean and clear of tool(s) and other items.
(c) Make sure that the components (or parts of components) removed to get access to other components are correctly installed and connected. Make sure that they operate correctly.
(d) If the maintenance engineer finds something incorrect, he must tell the related department.

Subtask 29-00-00-911-050-A

H. Torque Values
(1) Standard torque values for hydraulic fittings, nuts, jam nuts and others are given in (Ref. AMM TASK 20-21-12-911-001).
(2) Only non standard torque values are given in tasks in this chapter.
(3) Do the double torque procedure (Ref. AMM TASK 20-23-11-917-001).
(4) Mark the tightened union nuts and the locknut with a red line (Ref. AMM TASK 20-23-22-910-001).

Subtask 29-00-00-911-051-A

I. Hydraulic Connections

NOTE: Aircraft dispatch with hydraulic components isolated and plugs/caps installed is possible if it is permitted in the MMEL. Refer to SIL29-069 for more data on cap/plug installation.

(1) All the components and lines of the hydraulic system are connected through fittings of the same style or by bobbins. There are different types of connection:

Line to line
Line to line through a pressure bulkhead
Line to component
Component-to-support component.

NOTE: Some other manifolds have symmetrical bobbins with the same O-rings on the two sides. Thus the direction in which you install them is not important.

5. Close-up
Subtask 29-00-00-910-058-A

A. Put the aircraft back to the serviceable condition.
(1) Remove the container.
(2) Make sure that the work area is clean and clear of tools and other items.

[Rev.10 from 2021] 2026.04.01 03:56:18 UTC