AIRBUS A320NOSE LANDING GEAR

NITROGEN CHARGING PROCEDURE

Training Presentation

FOREWORD

These notes are supplied by Messier-Dowty for the limited purpose of familiarisation and general information support specific training course only, and may not be copied, disclosed to a third parties or used for any purpose other than which it is supplied, without the express written authority of Messier-Dowty.

Information contained herein is intended only as a general description to assist intelligent maintenance and systematic troubleshooting of subject systems or components described herein.

It is not the intent of Messier-Dowty that any training publication be used as a supplement to, or instead of, any official publication. Contents herein are subject to change without notice.

The reader of this manual is reminded that all values of pressure, temperature, speed, power etc., are chosen for their illustrative meaning only and are not necessarily representative of true values. For actual values of pressure the applicable Maintenance or Component Maintenance Manual must be consulted.

CONTENTS

NOSE LANDING GEAR

FUNCTIONAL DIAGRAM

NITROGEN FILLING VALVE

TOOLING

PREPARATION

NITROGEN CHARGING PROCEDURE

Nose Landing Gear Leg

1

OIL FILLING AND NITROGEN CHARGING VALVE

Functional Diagram

RETSTRICTOR VALVE

COMPRESSION

NITROGEN GAS

CYLINDER

RESTRICTOR

HYDRAULIC FLUID

EXTENSION

2

Nitrogen Charging Valve

A

SHOCK ABSORBER

DETAIL A

BLANKING CAP (7)

CHARGING VALVE(6)

Tooling:-Filing Assembly MS21930

1) Filling Connection

2) End Fitting

3) Knurled Shoulder

4) Seal

5) Plug

6) Charging Valve

7) Blanking Cap

8) Core

9) Wrench

Filling ConnectionEnd Fitting

Wrench

Plug

Blanking Cap

Charging Valve

Seal

Knurled Shoulder

Core

10) Nitrogen source and control valve.

11) Pressure Gauge.

12) Filling Hose.

13) Three-way Valve.

14) Control Valve.

15) Control Valve.

16) Nitrogen Supply Hose.

Nitrogen source and control valve (10)

Pressure Gauge (11)

Filling Hose (12)

Three-way Valve (13)

Control Valve (14)

Control Valve (15)

Nitrogen Supply Hose (16)

Tooling:-Nitrogen/ Hydraulic Supply and Tool Kit (NATO Box)

Nitrogen Charging Procedure - Preparation

1) Remove blanking plug (7) from charging valve (6)

2) Install the filling assembly (M21930) on the charging valve (6) as follows:-

a) Remove the plug (5)

b) Move the wrench (9) up the knurled shoulder (3)

and install the filling assembly on the charging valve (6)

c) Turn the core (8) of the filling assembly clockwise with the knurled shoulder (3)to install the seal (4) on the charging valve (6).

Warnings

MAKE SURE THAT THE AREA AROUND AIRCRAFT IS CLEAR OF PERSONS AND EQUIPMENT. WHEN YOU

PRESSURISE/DEPRESSURISE THE SHOCK ABSORBER, WITH THE AIRCRAFT WEIGHT ON THE GROUND, THE

AIRCRAFT WILL MOVE.

DO NOT LET HIGH PRESSURE GAS TOUCH YOUR SKIN. GAS BUBBLES IN YOUR BLOOD CAN KILL

YOU

and slowly turn the wrench (9) counterclockwise to open the charging valve (6)

3) Compress the shock absorber as follows:

a) Move the wrench (9) down

and release the nitrogen pressure.

b) Let the shock absorber compress completely.

c) When nitrogen pressure is released, turn the wrench (9) clockwise to close the charging valve (6).

4) Connect the nitrogen supply (10) and nitrogen supply hose (16) to the three way valve (13).

5) Connect the nitrogen filling hose (14) to the three way valve and install the air/hydraulic tool kit (NATO box) on the filling assembly.

Nitrogen Charging Procedure - Preparation cont..

Nitrogen Charging Procedure

1) Make note of the ambient temperature.

2) Pressurise the shock absorber with nitrogen as follows:

a) Turn the wrench (9) counterclockwise to open the charging valve (6).

b) Slowly open the control valve (15) from the nitrogen supply. Add nitrogen until shock absorber begins to extend

Nitrogen Charging Procedurec) Refer to Pressure - Extension graph to obtain the correct dimension ‘H’, relevant to the current ambient air temperature.

d) Add more nitrogen by opening control valve (15) or remove nitrogen by opening control valve (14) to achieve dimension

‘H’, as measured on the landing gear.

Example:

1000 PSI at 0º C (32º F) = 4.80in (121,9mm) extension

PR

ES

SU

RE

DIMENSION ‘H’

DIMENSION ‘H’

CONTROL VALVE (15)

CONTROL VALVE (14)

Nitrogen Charging ProcedureAFTER CHARGING

1) Check that the measurement of Dimension ‘H’, the pressure and the air temperature all agree wit the Pressure-Extension graph.

NOTE: If Dimension ‘H’ can not be achieved in accordance with the Pressure-Extension graph, the oil level within the shock absorber may be low. In the event of low oil level refer to the filling procedure.

2) Turn the wrench (9) clockwise to close the charging valve.

3) Close the control valve from the nitrogen supply source and disconnect the nitrogen supply hose (16) from the three-way valve (13)

4) Remove three-way valve (13) from the filling assembly.

Nitrogen Charging Procedure

5) Remove the filling assembly from the charging valve (6) as follows:-

a) Torque the charging valve (6) to between 0.5 and 0.8 m.daN (44.24 and 70.79lbf.in.)

b) Move the wrench (9) up the knurled shoulder (3).

c) Turn the knurled shoulder (3) counterclockwise to release the seal (4) from the charging valve (6).

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