NLG Shock Absorber Oil Replenishment and Nitrogen Filling (Aircraft on Jacks)

TASK 12-12-32-611-005-A
NLG Shock Absorber Oil Replenishment and Nitrogen Filling (Aircraft on Jacks)

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: 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.

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

WARNING: DO NOT LET COMPRESSED GAS TOUCH YOUR SKIN. THE GAS CAN GO THROUGH THE SKIN AND MAKE BUBBLES IN THE BLOOD. THIS CONDITION CAN KILL YOU.

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

ZONE: 711

1. Reason for the Job

NOTE: This procedure can be done with the aircraft fully lifted on jacks (Ref. Task 07-11-00-581-001) or lifted at the forward jacking point (Ref. Task 07-11-00-581-003).

NOTE: This procedure must be done a minimum of two hours after the last aircraft operation. This is to give time for the separation of the nitrogen from the oil in the shock absorber.

NOTE: After the servicing of the NLG shock absorber, nitrogen gets absorbed into the hydraulic fluid during the hours/days following the pressure charging operation. Thus the charge pressures given in the task are specified to compensate for the loss of pressure because of this phenomenon.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	1	CONTAINER 20L (5 USGAL)
No specific	AR	GAGE 200 BAR (2900 PSI) - PRESSURE, HYDRAULIC
No specific	AR	JACK - TROLLEY 500 MM (19,6 IN)
No specific	AR	MARKER - CHALK, STICK
No specific	AR	NITROGEN COMPRESSED SOURCE - GROUND
No specific	AR	PLATE - BLOW (SHOCK) ABSORBER
No specific	1	RULER - STEEL
No specific	AR	SAFETY BARRIER(S)
No specific	1	THERMOMETER -45 TO 70 DEG.C (-49 TO 158 DEG.F)
No specific	1	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.8 and 0.5 m.daN (70.80 and 44.25 lbf.in )
98D32203502000	2	SAFETY PIN - NLG DOOR
98F32001006000	1	GEAR FILLING KIT S-ABSOR
M21930	1	FILLING ASSEMBLY

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.02BBB9)	Mineral Hydraulic Fluid-Damper - -
(Material No.02CBB1)	Mineral Hydraulic Fluid & Additives-Damper Shock Struts -
(Material No.02CCC1)	Mineral Hydraulic Fluid & Additives-Damper Landing Gear -
(Material No.14CCB6)	Testing Medium-Leak Detection - Oxygen System

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
711	NOSE GEAR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 07-11-00-581-001-A	Lifting for Aircraft Maintenance Operations
TASK 07-11-00-581-003-A	Lifting of the Aircraft at the Forward Jacking Point, MLG Wheels on the Ground
TASK 07-11-00-586-001-A	Lowering of the Aircraft at Forward Jacking Point, MLG Wheels on the Ground
TASK 07-11-00-586-002-A	Lowering of the Aircraft for Maintenance Operations
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 32-00-00-481-001-A	Installation of the Safety Devices on the Landing Gears
TASK 32-00-00-481-002-A	Installation of the Safety Devices on the Landing Gear Doors
TASK 32-00-00-860-001-A	Flight Configuration Precautions with Electrical Power
TASK 32-00-00-860-001-A-01	Flight Configuration Precautions without Electrical Power
TASK 32-22-00-010-001-A	Nose Gear Doors - Ground Doors Opening
TASK 32-22-00-410-001-A	Nose Gear Doors - Ground Doors Closing
NLG Shock Absorber Replenishment - Location and Detail
NLG Shock Absorber - Filling System
NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL
Pressure/Temperature Table - Shock Absorber Fully Extended
NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL
NLG Shock Absorber - Collar and Shim Position ** ON A/C NOT FOR ALL
NLG Shock Absorber - Reference Mark R and R1 Detail ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 12-12-32-941-064-A

A. Safety Precautions
(1) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(2) Put a WARNING NOTICE(S) in the cockpit, to tell persons not to operate the landing gear or the landing gear doors.
(3) Make sure that the ground safety locks are installed on the landing gear (Ref. AMM TASK 32-00-00-481-001).

Subtask 12-12-32-869-052-A

B. Flight Configuration Precautions
(1) If the electrical power is not necessary for other maintenance tasks, de-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002). Then, it is not necessary to operate the LGCIU circuit breakers.
(2) If the electrical power is necessary, do the flight configuration precautions with electrical power before you open the Landing Gear Control and Interface Unit (LGCIU) circuit breakers (Ref. AMM TASK 32-00-00-860-001).

Subtask 12-12-32-582-052-A

C. Lift the Aircraft on Jacks
(1) Lift the aircraft on jacks (Ref. AMM TASK 07-11-00-581-001) or (Ref. AMM TASK 07-11-00-581-003).

NOTE: Do not do the check immediately after the aircraft is lifted. The shock absorber charge pressure should not be measured until the aircraft has been on jacks for fifteen minutes. This will let the shock absorber pressure become stable and make sure that the value recorded is accurate.

Subtask 12-12-32-010-052-A

D. Get Access

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE LANDING GEAR DOORS ARE CLEAR.

(1) Open the NLG doors (Ref. AMM TASK 32-22-00-010-001).
(2) Install the 98D32203502000 SAFETY PIN - NLG DOOR in the linkage of each forward NLG door (Ref. AMM TASK 32-00-00-481-002).
(3) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position at the NLG.

4. Procedure
Subtask 12-12-32-614-059-A

A. Preparation for Replenishment

WARNING: DO NOT GET HYDRAULIC FLUID ON YOUR SKIN, IN YOUR EYES OR IN YOUR MOUTH. HYDRAULIC FLUID IS POISONOUS AND CAN GO THROUGH YOUR SKIN AND INTO YOUR BODY. FLUSH HYDRAULIC FLUID FROM YOUR EYES, MOUTH OR SKIN WITH WATER. GET MEDICAL AID IF YOU GET HYDRAULIC FLUID IN YOUR EYES OR MOUTH.

(1) Install the 98F32001006000 GEAR FILLING KIT S-ABSOR on the M21930 FILLING ASSEMBLY as follows:

NLG Shock Absorber Replenishment - Location and Detail

NLG Shock Absorber - Filling System

(a) Connect the hydraulic source hose (17) to the hydraulic source (16).

NOTE: The hydraulic source (16) can be a GAGE 200 BAR (2900 PSI) - PRESSURE, HYDRAULIC or a hydraulic-fluid source tank 8 l (2 USgal). If a tank is used, it must be in position above the charging valve (6).

(b) Make sure that the control valves (13) and (19) of the three-way valve (12) are closed.
(c) Connect the hydraulic source hose (17) to the three-way valve (12).
(d) Connect the filling hose (11) to the three-way valve (12).
(e) Remove the blanking cap (1) and the plug from the M21930 FILLING ASSEMBLY.
(f) Connect the filling hose (11) to the end fitting (2) of the M21930 FILLING ASSEMBLY.
(g) Connect the translucent bleed hose (14) between the three-way valve (12) and the CONTAINER 20L (5 USGAL) (15).
(h) Fill the hydraulic source (16) with Mineral Hydraulic Fluid-Damper - - (Material No.02BBB9) or Mineral Hydraulic Fluid & Additives-Damper Shock Struts - (Material No.02CBB1) or Mineral Hydraulic Fluid & Additives-Damper Landing Gear - (Material No.02CCC1) .

NOTE: Mineral Hydraulic Fluid-Damper - - (Material No.02BBB9) , Mineral Hydraulic Fluid & Additives-Damper Shock Struts - (Material No.02CBB1) and Mineral Hydraulic Fluid & Additives-Damper Landing Gear - (Material No.02CCC1) can be mixed in all applicable maintenance tasks and in all quantities.

(2) Install the M21930 FILLING ASSEMBLY on the charging valve (6) as follows:

NLG Shock Absorber Replenishment - Location and Detail

(a) Remove the blanking cap (7) from the charging valve (6).
(b) Move the wrench (9) up to the knurled shoulder (3) and install the M21930 FILLING ASSEMBLY on the charging valve (6).
(c) Turn the core (8) of the M21930 FILLING ASSEMBLY clockwise with the knurled shoulder (3).
(d) Install the seal (4) on the charging valve (6).
(3) Make sure that the 98F32001006000 GEAR FILLING KIT S-ABSOR is correctly installed and does not leak.
(4) Deflate the shock absorber as follows:

WARNING: MAKE SURE THAT THE AREA AROUND THE AIRCRAFT IS CLEAR OF PERSONS AND EQUIPMENT. WHEN YOU PRESSURIZE/DEPRESSURIZE THE SHOCK ABSORBER, WITH THE AIRCRAFT WEIGHT ON THE GROUND, THE AIRCRAFT WILL MOVE.

WARNING: DO NOT LET COMPRESSED GAS TOUCH YOUR SKIN. THE GAS CAN GO THROUGH THE SKIN AND MAKE BUBBLES IN THE BLOOD. THIS CONDITION CAN KILL YOU.

(a) Move the wrench (9) down and turn counterclockwise to open the charging valve (6).
(b) Make sure that you deflate the shock absorber slowly.

NOTE: This will prevent the fluid to bleed with the gas from the shock absorber.

NOTE: This is to release the nitrogen pressure and let the shock absorber fully deflate. The pressure gage (10) will show approximately 1 bar (15 psi) when the shock absorber is fully deflated.

(d) When all the nitrogen pressure is released, close the control valve (13) on the three-way valve (12) .

Subtask 12-12-32-611-052-A ** ON A/C NOT FOR ALL

B. Replenishment of the NLG Shock Absorber

WARNING: MAKE SURE THAT THERE ARE NO PERSONS OR EQUIPMENT NEAR THE L/G SHOCK ABSORBER DURING REPLENISHMENT. THERE IS A RISK THAT PRESSURIZED GASES OR FLUID CAN ESCAPE AND CAUSE INJURY OR DAMAGE.

CAUTION: DO NOT LET THE HYDRAULIC PRESSURE INCREASE TO MORE THAN 22bar (319psi). THIS WILL PREVENT INTERNAL DAMAGE.

(1) Fill the NLG shock absorber with Mineral Hydraulic Fluid-Damper - - (Material No.02BBB9) or Mineral Hydraulic Fluid & Additives-Damper Shock Struts - (Material No.02CBB1) or Mineral Hydraulic Fluid & Additives-Damper Landing Gear - (Material No.02CCC1) , as follows:

(a) Make sure that you compress/extend the NLG shock absorber slowly:

To prevent possible shock when the NLG shock absorber gets to the limit of its travel
To not let the gas mix with the oil in the NLG shock absorber.

(b) If you use the hydraulic fluid source-tank as the hydraulic source (16) to fill the NLG shock absorber, do the steps that follow:
1 Before you do the procedure make sure that the hydraulic fluid-source tank (16) is in position above the charging valve (6).
2 Put the JACK - TROLLEY 500 MM (19,6 IN) below the jacking dome of the NLG shock absorber.
3 Open the control valve (13) on the three-way valve (12).

CAUTION: MAKE SURE THAT THE SHOCK ABSORBER COMPRESSES WHEN THE JACK TROLLEY IS USED. THIS WILL PREVENT DAMAGE TO THE AIRCRAFT.

4 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Dimension H must be 19 mm (0.7480 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

NOTE: Use an applicable RULER - STEEL to measure dimension H.

5 Close the control valve (13) on the three-way valve (12).
6 Turn the wrench (9) clockwise and close the charging valve (6).
7 Release the jack load and let the leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

8 Let the shock absorber become stable, continue after a minimum of 15 minutes.

NOTE: This will isolate the gas from the fluid.

NOTE: The indication of the pressure gage (10) does not apply during this step.

9 Open the control valve (13) on the three-way valve (12).
10 Turn the wrench (9) counterclockwise to open the charging valve (6).
11 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber.
12 Close the control valve (13) on the three-way valve (12).
13 Open the control valve (19) on the three-way valve (12).
14 Release the jack load and let the NLG leg fully extend for hydraulic fluid to fill the NLG shock absorber. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

15 Let the hydraulic fluid fill the NLG shock absorber, continue after a minimum of 10 minutes.
16 Close the control valve (19) on the three-way valve (12).
17 Open the control valve (13) on the three-way valve (12).
18 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Monitor the hydraulic fluid that goes into the drain container (15) through the translucent bleed hose (14).

NOTE: When the NLG shock absorber is first compressed it is possible that no hydraulic fluid goes into the container. This can occur if the NLG shock absorber is empty of fluid, or the fluid level is low.

19 Close the control valve (13) on the three-way valve (12).
20 Open the control valve (19) on the three-way valve (12).
21 Release the jack load and let the NLG leg fully extend for hydraulic fluid to fill the NLG shock absorber. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

22 Let the hydraulic fluid fill the NLG shock absorber, continue after a minimum of 20 minutes.
23 Close the control valve (19) on the three-way valve (12).
24 Open the control valve (13) on the three-way valve (12).
25 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Monitor the hydraulic fluid that goes into the drain container (15) through the translucent bleed hose (14).
26 The hydraulic fluid must be released from the NLG shock absorber during the NLG shock absorber compression.

NOTE: If hydraulic fluid is not released, do steps 4.B.(1)(b)19_ thru 4.B.(1)(b)25_ again.

27 The fluid released from the shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, do steps 4.B.(1)(b)5_ thru 4.B.(1)(b)25_ again.

28 Close the control valve (13) on the three-way valve (12).
29 Turn the wrench (9) clockwise to close the charging valve (6).
30 Disconnect the hydraulic source hose (17) from the three-way valve (12).
31 Disconnect the filling hose (11) from the M21930 FILLING ASSEMBLY. Put the free end of the filling hose (11) in the drain container (15) to drain the hydraulic fluid.
32 Tighten the filling hose (11) on the M21930 FILLING ASSEMBLY.
33 Remove the translucent bleed hose (14) from the three-way valve (12).
(c) If you use the hydraulic power-supply inflation bench as the hydraulic source (16) to fill the NLG shock absorber, do the steps that follow:
1 Put the JACK - TROLLEY 500 MM (19,6 IN) below the jacking dome of the NLG shock absorber.
2 Open the control valve (13) on the three-way valve (12).

CAUTION: MAKE SURE THAT THE SHOCK ABSORBER COMPRESSES WHEN THE JACK TROLLEY IS USED. THIS WILL PREVENT DAMAGE TO THE AIRCRAFT.

3 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Dimension H must be 19 mm (0.7480 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

4 Close the control valve (13) on the three way valve (12).
5 Turn the wrench (9) clockwise to close the charging valve (6).
6 Release the jack load and let the NLG leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

7 Let the NLG shock absorber become stable, continue after a minimum of 15 minutes.

NOTE: This will isolate the gas from the fluid.

8 Open the control valve (13) on the three-way valve (12).
9 Turn the wrench (9) counterclockwise to open the charging valve (6).
10 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber.
11 Close the control valve (13) on the three-way valve (12).
12 Turn the wrench (9) clockwise to close the charging valve (6).
13 Disconnect the filling hose (11) from the M21930 FILLING ASSEMBLY. Put the free end of the filling hose (11) in the drain container to drain the hydraulic fluid.
14 Operate the hydraulic power-supply inflation bench (16) and slowly open the control valve (19) on the three-way valve (12). Bleed the filling hose (11) with hydraulic fluid.
15 Close the control valve (19) on the three-way valve (12).
16 Connect the filling hose (11) to the M21930 FILLING ASSEMBLY.
17 Turn the wrench (9) counterclockwise to open the charging valve (6).
18 Close the control valve (13) on the three-way valve (12).
19 Open the control valve (19) on the three-way valve (12).

WARNING: MAKE SURE THAT THE TROLLEY JACK CANNOT TOUCH THE SHOCK ABSORBER DURING SHOCK ABSORBER EXTENSION.

20 Release the jack load and lower the JACK - TROLLEY 500 MM (19,6 IN) fully.
21 Operate the hydraulic power-supply inflation bench (16) and slowly fill the NLG shock absorber with fluid until the leg is fully extended. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

22 When the NLG leg is fully extended, continue to inflate the NLG shock absorber until the pressure is 10 bar (145 psi).
23 Close the control valve (19) on the three-way valve (12).
24 Slowly open the control valve (13) on the three-way valve (12).
25 Use the JACK - TROLLEY 500 MM (19,6 IN) to slowly compress the NLG shock absorber until dimension H is 300 mm (11.8110 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

26 Close the control valve (13) on the three-way valve (12).
27 Turn the wrench (9) clockwise to close the charging valve (6).
28 Release the jack load and let the leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

29 Let the NLG shock absorber become stable, continue after a minimum of 10 minutes.

NOTE: This will isolate the gas from the fluid.

30 Open the control valve (13) on the three-way valve (12).
31 Turn the wrench (9) counterclockwise to open the charging valve (6).
32 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Monitor the hydraulic fluid that goes into the drain container (15).
33 The hydraulic fluid must be released from the NLG shock absorber during the shock absorber compression.

NOTE: If hydraulic fluid is not released, do steps 4.B.(1)(c)18_ to 4.B.(1)(c)32_ again.

34 The fluid released from the NLG shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, do steps 4.B.(1)(c) 18_ to 4.B.(1)(c)32_ again.

35 Close the control valve (13) on the three-way valve (12).
36 Turn the wrench (9) clockwise to close the charging valve (6).
37 Disconnect the hydraulic source hose (17) from the three-way valve (12).
38 Disconnect the filling hose (11) from the M21930 FILLING ASSEMBLY. Put the free end of the filling hose (11) in the drain container (15) to drain the hydraulic fluid.
39 Remove the translucent bleed hose (14) from the three-way valve (12).
(2) Fill the NLG shock absorber with nitrogen gas, as follows:

WARNING: DO NOT LET COMPRESSED GAS TOUCH YOUR SKIN. THE GAS CAN GO THROUGH THE SKIN AND MAKE BUBBLES IN THE BLOOD. THIS CONDITION CAN KILL YOU.

CAUTION: ALWAYS ADD NITROGEN SLOWLY WHEN YOU PRESSURIZE THE SHOCK ABSORBER. IF YOU ADD THE NITROGEN TOO QUICKLY, THE TEMPERATURE WILL INCREASE AND HAVE AN EFFECT ON THE SHOCK ABSORBER PRESSURE.

(a) Connect the nitrogen source hose (18) of the NITROGEN COMPRESSED SOURCE - GROUND to the three-way valve (12).
(b) Open the control valve (19) on the three-way valve (12).
(c) Slowly open the control valve of the nitrogen source to release nitrogen pressure and bleed the circuit with dry nitrogen.
(d) Close the control valve of the nitrogen source.
(e) Close the control valve (19) on the three-way valve (12).
(f) Connect the filling hose (11) to the M21930 FILLING ASSEMBLY.
(g) Lower the JACK - TROLLEY 500 MM (19,6 IN) to let the NLG shock absorber extend fully. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.). Make sure that the jack is disengaged from the NLG shock absorber jacking dome.

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

(h) Use a THERMOMETER -45 TO 70 DEG.C (-49 TO 158 DEG.F) to measure and record the temperature adjacent to the charging valve (6). Make sure that the thermometer touches the NLG shock absorber outer-cylinder. If possible, measure the temperature at the top part of the cylinder (through the vent hole) at the aft part of the main fitting.

NLG Shock Absorber Replenishment - Location and Detail ** ON A/C NOT FOR ALL

(i) Refer to the pressure/temperature table to know the NLG shock absorber charge pressure with relation to the temperature measured at step 4.B.(2)(h).

Pressure/Temperature Table - Shock Absorber Fully Extended ** ON A/C NOT FOR ALL

(j) Turn the wrench (9) counterclockwise to open the charging valve (6).
(k) Open the control of the nitrogen source.
(l) Slowly open the control valve (19) on the three-way valve (12). This is to inflate the NLG shock absorber up to the necessary charge pressure.
(m) Close the control valve (19) on the three-way valve (12).
(n) Let the pressure become stable, continue after a minimum of 15 minutes.
(o) Make sure that the pressure/temperature conditions are the same as in steps 4.B.(2)(h) and 4.B.(2)(i). If not, do steps 4.B.(2)(l) thru 4.B.(2)(o) again.
(p) Close the control valve (19) on the three-way valve (12).
(q) Turn the wrench (9) clockwise to close the charging valve (6).
(r) Close the control valve of the nitrogen source.
(s) Slowly open the control valve (13) on the three-way valve (12), to release the nitrogen pressure from the filling system.
(t) Remove the filling hose (11) and the M21930 FILLING ASSEMBLY from the charging valve (6).
(u) TORQUE the charging valve (6) to between 0.8 and 0.5 m.daN (70.80 and 44.25 lbf.in )

.
(v) Use Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to do a leak check of the charging valve (6).
(w) Install the blanking cap (7) on the charging valve (6).

Subtask 12-12-32-611-052-C ** ON A/C NOT FOR ALL

B. Replenishment of the NLG Shock Absorber

WARNING: MAKE SURE THAT THERE ARE NO PERSONS OR EQUIPMENT NEAR THE L/G SHOCK ABSORBER DURING REPLENISHMENT. THERE IS A RISK THAT PRESSURIZED GASES OR FLUID CAN ESCAPE AND CAUSE INJURY OR DAMAGE.

CAUTION: DO NOT LET THE HYDRAULIC PRESSURE INCREASE TO MORE THAN 22bar (319psi). THIS WILL PREVENT INTERNAL DAMAGE.

(a) Make sure that you compress/extend the NLG shock absorber slowly:

To prevent possible shock when the NLG shock absorber gets to the limit of its travel
To not let the gas mix with the oil in the NLG shock absorber.

(b) If you use the hydraulic fluid source-tank as the hydraulic source (16) to fill the NLG shock absorber, do the steps that follow:
1 Before you do the procedure make sure that the hydraulic fluid source tank (16) is in position above the charging valve (6).
2 Put the JACK - TROLLEY 500 MM (19,6 IN) under the jacking dome of the NLG shock absorber.
3 Open the control valve (13) on the three-way valve (12).

CAUTION: MAKE SURE THAT THE SHOCK ABSORBER COMPRESSES WHEN THE JACK TROLLEY IS USED. THIS WILL PREVENT DAMAGE TO THE AIRCRAFT.

4 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Dimension H must be 19 mm (0.7480 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

NOTE: Use an applicable RULER - STEEL to measure dimension H.

5 Close the control valve (13) on the three-way valve (12).
6 Turn the wrench (9) clockwise to close the charging valve (6).
7 Release the jack load and let the NLG leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

8 Let the NLG shock absorber become stable, continue after 15 minutes.

NOTE: This will isolate the gas from the fluid.

NOTE: The indication of the pressure gage (10) does not apply during this step.

9 Open the control valve (13) on the three-way valve (12).
10 Turn the wrench (9) counterclockwise to open the charging valve (6).
11 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber.
12 Close the control valve (13) on the three-way valve (12).
13 Open the control valve (19) on the three-way valve (12).
14 Release the jack load and let the leg fully extend for hydraulic fluid to fill the NLG shock absorber. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

NOTE: When the NLG shock absorber is first compressed, it is possible that no hydraulic fluid goes into the container. This can occur if the NLG shock absorber is empty of fluid, or the fluid level is low.

19 The fluid released from the NLG shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, do steps 4.B.(1)(b)5_ thru 4.B.(1)(b)18_ again.

20 In the steps that follow, the PLATE - BLOW (SHOCK) ABSORBER is used to set the NLG shock absorber. The KIT-SHOCK ABSORBER, NLG has three parts:

A COLLAR (Q47118)
A LEVELLING SHIM (Q47119)
A TORQUE COLLAR (S128/7ZY).

a Close the control valve (13) on the three-way valve (12).
b Put the COLLAR (Q47118) at the bottom of the sliding tube. The upper surface of the COLLAR (Q47118) must touch the lower surface of the turning tube lower bearing.

NLG Shock Absorber - Collar and Shim Position ** ON A/C NOT FOR ALL

NOTE: If you find a problem, make sure the COLLAR (Q47118) is correctly positioned.

c Hold the COLLAR in position with the TORQUE COLLAR (S128/7ZY).
d Open the control valve (19) on the three-way valve (12).
e Release the jack load and let the NLG leg fully extend for hydraulic fluid to fill the NLG shock absorber. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

f Let the hydraulic fluid fill the NLG shock absorber, continue after a minimum of 20 minutes.
g Close the control valve (19) on the three-way valve (12).
h Install the LEVELLING SHIM (Q47119) on the sliding tube. Put the LEVELLING SHIM against the upper surface of the COLLAR then tighten it on the sliding tube.
i Open the control valve (13) on the three-way valve (12).
j Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Monitor the hydraulic fluid that goes into the drain container (15) through the translucent bleed hose (14).

NOTE: The COLLAR and the LEVELLING SHIM must not move on the sliding tube.

k The hydraulic fluid must be released from the NLG shock absorber during the NLG shock absorber compression.

NOTE: If hydraulic fluid is not released, remove the LEVELLING SHIM (Q47119) and do steps 4.B.(1)(b)20_a_ thru 4.B.(1)(b)20_j_ again.

l The fluid released from the NLG shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, remove the LEVELLING SHIM (Q47119) and do steps 4.B.(1)(b)5_ thru 4.B.(1)(b)20_k_ again.

m Close the control valve (13) on the three-way valve (12).
n Turn the wrench (9) clockwise to close the charging valve (6).
o Remove the LEVELLING SHIM, TORQUE COLLAR and COLLAR from the sliding tube.
21 If the KIT-SHOCK ABSORBER, NLG (AC21975000) is not available, do the steps that follow:
a Close the control valve on the three-way valve (12).
b Use a MARKER - CHALK, STICK to make a reference mark (R) on the sliding tube of the NLG shock absorber. The mark (R) must be level with the lower surface of the turning tube.

NLG Shock Absorber - Reference Mark R and R1 Detail ** ON A/C NOT FOR ALL

c Open the control valve (19) on the three-way valve (12).
d Release the jack load and let the NLG leg fully extend for hydraulic fluid to fill the NLG shock absorber. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

e Let the hydraulic fluid fill the NLG shock absorber, continue after a minimum of 20 minutes.
f Close the control valve (19) on the three-way valve (12).
g Use a MARKER - CHALK, STICK to make a second reference mark (R1) on the sliding tube of the NLG shock absorber. The second mark (R1) must be 25 mm (0.9843 in.) above the initial mark (R) made on the sliding tube.
h Open the control valve (13) on the three-way valve (12).

CAUTION: DO NOT COMPRESS THE SHOCK ABSORBER FULLY. IF THE BOTTOM OF THE TURNING TUBE GOES BELOW THE SECOND MARK (R1), THE FLUID LEVEL WILL BE INCORRECT (TOO LOW).

i Use the trolley jack to compress the NLG shock absorber. Compress the NLG shock absorber until the second mark (R1) is level with the bottom of the sliding tube. Monitor the hydraulic fluid that goes into the drain container (15) through the translucent bleed hose (14).
j The hydraulic fluid must be released from the NLG shock absorber during the NLG shock absorber compression.

NOTE: If hydraulic fluid is not released, do steps 4.B.(1)(b)21_a_ thru 4.B.(1)(b)21_i_ again.

k The fluid released from the shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, do steps 4.B.(1)(b)5_ thru 4.B.(1)(b)21_j_ again.

l Close the control valve (13) on the three-way valve (12).
m Turn the wrench (9) clockwise to close the charging valve (6).
22 Disconnect the hydraulic source hose (17) from the three-way valve (12).
23 Disconnect the filling hose (11) on the M21930 FILLING ASSEMBLY to let the hydraulic fluid drain into the drain container (15).
24 Tighten the filling hose (11) on the M21930 FILLING ASSEMBLY.
25 Remove the translucent bleed hose (14) from the three-way valve (12).
(c) If you use the hydraulic power-supply inflation bench as the hydraulic source (16) to fill the NLG shock absorber, do the steps that follow:
1 Put the JACK - TROLLEY 500 MM (19,6 IN) under the jacking dome of the NLG shock absorber.
2 Open the control valve (13) on the three-way valve (12).

CAUTION: MAKE SURE THAT THE SHOCK ABSORBER COMPRESSES WHEN THE JACK TROLLEY IS USED. THIS WILL PREVENT DAMAGE TO THE AIRCRAFT.

3 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Dimension H must be 19 mm (0.7480 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

7 Let the NLG shock absorber become stable, continue after a minimum of 15 minutes.

NOTE: This will isolate the gas from the fluid.

8 Open the control valve (13) on the three-way valve (12).
9 Turn the wrench (9) counterclockwise to open the charging valve (6).
10 Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber.
11 Close the control valve (13) on the three-way valve (12).
12 Turn the wrench (9) clockwise to close the charging valve (6).
13 Disconnect the filling hose (11) from the M21930 FILLING ASSEMBLY. Put the free end of the filling hose (11) in the drain container to drain the hydraulic fluid.
14 Operate the hydraulic power supply bench (16) and slowly open the control valve (19) on the three-way valve (12). Bleed the filling hose (11) with hydraulic fluid.
15 Close the control valve (19) on the three-way valve (12).
16 Connect the filling hose (11) to the M21930 FILLING ASSEMBLY.
17 Turn the wrench (9) counterclockwise to open the charging valve (6).
18 In the steps that follow, the PLATE - BLOW (SHOCK) ABSORBER is used to set the NLG shock absorber. The KIT-SHOCK ABSORBER, NLG has three parts:

A COLLAR (Q47118)
A LEVELLING SHIM (Q47119)
A TORQUE COLLAR (S128/7ZY).

a Close the control valve (13) on the three-way valve (12).
b Open the control valve (19) on the three-way valve (12).

WARNING: MAKE SURE THAT THE TROLLEY JACK CANNOT TOUCH THE SHOCK ABSORBER DURING SHOCK ABSORBER EXTENSION.

c Release the jack load and lower the JACK - TROLLEY 500 MM (19,6 IN) fully.
d Operate the hydraulic power-supply bench (16) and slowly fill the NLG shock absorber with fluid until the NLG leg is fully extended. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

e When the leg is fully extended, continue to inflate the NLG shock absorber until the pressure is 10 bar (145 psi).
f Close the control valve (19) on the three-way valve (12).
g Slowly open the control valve (13) on the three-way valve (12).
h Use the JACK - TROLLEY 500 MM (19,6 IN) to slowly compress the NLG shock absorber until dimension H is 300 mm (11.8110 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

i Close the control valve (13) on the three-way valve (12).
j Turn the wrench (9) clockwise to close the charging valve (6).
k Put the COLLAR (Q47118) at the bottom of the sliding tube. The upper surface of the COLLAR (Q47118) must touch the lower surface of the turning tube lower bearing.

NLG Shock Absorber - Collar and Shim Position ** ON A/C NOT FOR ALL

NOTE: If you find a problem, make sure the COLLAR (Q47118) is correctly positioned.

l Hold the COLLAR in position with the TORQUE COLLAR (S128/7ZY).
m Release the jack load and let the NLG leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

n Let the NLG shock absorber become stable, continue after a minimum of 10 minutes.

NOTE: This will isolate the gas from the fluid.

o Install the LEVELLING SHIM (Q47119) on the sliding tube. Position the LEVELLING SHIM against the upper surface of the COLLAR then tighten it on the sliding tube.
p Open the control valve (13) on the three-way valve (12).
q Turn the wrench (9) counterclockwise to open the charging valve (6).
r Use the JACK - TROLLEY 500 MM (19,6 IN) to fully compress the NLG shock absorber. Monitor the hydraulic fluid that goes into the drain container (15).

NOTE: The COLLAR and the LEVELLING SHIM must not move on the sliding tube.

s The hydraulic fluid must be released from the NLG shock absorber during the NLG shock absorber compression.

NOTE: If hydraulic fluid is not released, remove the LEVELLING SHIM (Q47119) and do steps 4.B.(1)(c)18_a_ to 4.B.(1)(c)18_r_ again.

t The fluid released from the shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, remove the LEVELLING SHIM (Q47119) and do steps 4.B.(1)(c)18_a_ to 4.B.(1)(c)18_s_ again.

u Close the control valve (13) on the three-way valve (12).
v Turn the wrench (9) clockwise to close the charging valve (6).
w Remove the LEVELLING SHIM, TORQUE COLLAR and COLLAR from the sliding tube.
19 If the KIT-SHOCK ABSORBER, NLG (AC21975000) is not available, do the steps that follow:
a Close the control valve (13) on the three-way valve (12).
b Open the control valve (19) on the three-way valve (12).
c Use a MARKER - CHALK, STICK to make a reference mark (R) on the sliding tube of the shock absorber. The mark (R) must be level with the lower surface of the sliding tube.

NLG Shock Absorber - Reference Mark R and R1 Detail ** ON A/C NOT FOR ALL

WARNING: MAKE SURE THAT THE TROLLEY JACK CANNOT TOUCH THE SHOCK ABSORBER DURING SHOCK ABSORBER EXTENSION.

d Release the jack load and lower the trolley jack fully.
e Operate the hydraulic power-supply bench (16) and slowly fill the NLG shock absorber with fluid until the NLG leg is fully extended. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

f When the NLG leg is fully extended, continue to inflate the NLG shock absorber until the pressure is 10 bar (145 psi).
g Close the control valve (19) on the three-way valve (12).
h Slowly open the control valve (13) on the three-way valve (12).
i Use the trolley jack to slowly compress the NLG shock absorber until dimension H is 300 mm (11.8110 in.).
j Close the control valve (13) on the three-way valve (12).
k Turn the wrench (9) clockwise to close the charging valve (6).
l Release the jack load and let the NLG leg fully extend. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.).

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

m Let the NLG shock absorber become stable, continue after a minimum of 10 minutes.

NOTE: This will isolate the gas from the fluid.

n Use a MARKER - CHALK, STICK to make a second reference mark (R1) on the sliding tube of the NLG shock absorber. The second mark (R1) must be 25 mm (0.9843 in.) above the initial mark (R) made on the sliding tube.

NLG Shock Absorber - Reference Mark R and R1 Detail ** ON A/C NOT FOR ALL

o Open the control valve (13) on the three-way valve (12).
p Turn the wrench (9) counterclockwise to open the charging valve (6).

CAUTION: DO NOT COMPRESS THE SHOCK ABSORBER FULLY. IF THE BOTTOM OF THE TURNING TUBE GOES BELOW THE SECOND MARK (R1), THE FLUID LEVEL WILL BE INCORRECT (TOO LOW).

q Use the trolley jack to compress the NLG shock absorber. Compress the NLG shock absorber until the second mark (R1) is level with the bottom of the sliding tube. Monitor the hydraulic fluid that goes into the drain container (15).
r The hydraulic fluid must be released from the NLG shock absorber during the NLG shock absorber compression.

NOTE: If hydraulic fluid is not released, do steps 4.B.(1)(c)19_a_ to 4.B.(1)(c)19_q_ again.

s The fluid released from the shock absorber through the translucent bleed hose (14) must not contain gas bubbles or emulsion.

NOTE: If gas bubbles or emulsion are found, do steps 4.B.(1)(c)19_a_ to 4.B.(1)(c)19_r_ again.

t Close the control valve (13) on the three-way valve (12).
u Turn the wrench (9) clockwise to close the charging valve (6).
20 Disconnect the hydraulic source hose (17) from the three-way valve (12).
21 Disconnect the filling hose (11) from the M21930 FILLING ASSEMBLY. Put the free end of the filling hose (11) in the drain container (15) to drain the hydraulic fluid.
22 Remove the translucent bleed hose (14) from the three-way valve (12).
(2) Fill the NLG shock absorber with nitrogen gas, as follows:

WARNING: DO NOT LET COMPRESSED GAS TOUCH YOUR SKIN. THE GAS CAN GO THROUGH THE SKIN AND MAKE BUBBLES IN THE BLOOD. THIS CONDITION CAN KILL YOU.

CAUTION: ALWAYS ADD NITROGEN SLOWLY WHEN YOU PRESSURIZE THE SHOCK ABSORBER. IF YOU ADD THE NITROGEN TOO QUICKLY, THE TEMPERATURE WILL INCREASE AND HAVE AN EFFECT ON THE SHOCK ABSORBER PRESSURE.

(a) Connect the nitrogen source hose (18) of the NITROGEN COMPRESSED SOURCE - GROUND to the three-way valve (12).
(b) Open the control valve (19) on the three-way valve (12).
(c) Slowly open the control of the nitrogen source to release nitrogen pressure and bleed the circuit with dry nitrogen.
(d) Close the control of the nitrogen source.
(e) Close the control valve (19) on the three-way valve (12).
(f) Connect the filling hose (11) to the M21930 FILLING ASSEMBLY.
(g) Lower the JACK - TROLLEY 500 MM (19,6 IN) to let the NLG shock absorber extend fully. Dimension H must be 449 mm (17.6772 in.) plus or minus 2 mm (0.0787 in.). Make sure that the jack is disengaged from the NLG shock absorber jacking dome.

NLG Shock Absorber - Dimension H ** ON A/C NOT FOR ALL

(h) Use a THERMOMETER -45 TO 70 DEG.C (-49 TO 158 DEG.F) to measure and record the temperature of the NLG shock absorber, adjacent to the charging valve (6). Make sure that the thermometer touches the NLG shock absorber outer-cylinder. If possible, measure the temperature at the top part of the cylinder (through the vent hole) at the aft part of the main fitting.

NLG Shock Absorber Replenishment - Location and Detail

(i) Refer to the pressure/temperature table to know the NLG shock absorber charge pressure with relation to the temperature measured at step 4.B.(2)(h).

Pressure/Temperature Table - Shock Absorber Fully Extended

(j) Turn the wrench (9) counterclockwise to open the charging valve (6).
(k) Open the control of the nitrogen source.
(l) Slowly open the control valve (19) on the three-way valve (12). This is to inflate the NLG shock absorber up to the necessary charge pressure.
(m) Close the control valve (20) on the three-way valve (12).
(n) Let the pressure become stable, continue after a minimum of 15 minutes.
(o) Make sure that the pressure/temperature conditions are the same as in steps 4.B.(2)(h) and 4.B.(2)(i). If not, do steps 4.B.(2)(l) thru 4.B.(2)(o) again.
(p) Close the control valve (19) on the three-way valve (12).
(q) Turn the wrench (9) clockwise to close the charging valve (6).
(r) Close the control valve of the nitrogen source.
(s) Slowly open the control valve (13) on the three-way valve (12), to release the nitrogen pressure from the filling system.
(t) Remove the filling hose (11) from the M21930 FILLING ASSEMBLY.
(u) TORQUE the charging valve (6) to between 0.8 and 0.5 m.daN (70.80 and 44.25 lbf.in )

.
(v) Use Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to do a leak check of the charging valve (6).
(w) Install the blanking cap (7) on the charging valve (6).

Subtask 12-12-32-942-060-A

C. Removal of the Equipment
(1) Remove the 98F32001006000 GEAR FILLING KIT S-ABSOR.
(2) Remove the JACK - TROLLEY 500 MM (19,6 IN).
(3) Remove the access platform(s).
(4) Make sure that the work area is clean and clear of tools and other items.

Subtask 12-12-32-410-052-A

D. Close Access
(1) Remove the 98D32203502000 SAFETY PIN - NLG DOOR from the linkage of each forward NLG door (Ref. AMM TASK 32-00-00-481-001).
(2) Close the NLG doors (Ref. AMM TASK 32-22-00-410-001).

Subtask 12-12-32-869-053-A

E. Ground Configuration
(1) If you opened the LGCIU circuit breakers, make sure that the flight configuration precautions with electrical power were obeyed (Ref. AMM TASK 32-00-00-860-001).

Subtask 12-12-32-586-051-A

F. Lower the Aircraft
(1) Lower the aircraft onto its wheels (Ref. AMM TASK 07-11-00-586-002) or (Ref. AMM TASK 07-11-00-586-001).

5. Close-up
Subtask 12-12-32-942-061-A

A. Removal of the Equipment
(1) Remove the SAFETY BARRIER(S).
(2) Remove the WARNING NOTICE(S).
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.03.31 22:54:46 UTC