Adjustment of the MLG Downlock Proximity Sensors

TASK 32-31-73-820-001-A
Adjustment of the MLG Downlock Proximity Sensors

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

FIN: 14GA
FIN: 15GA
FIN: 16GA
FIN: 17GA ** ON A/C NOT FOR ALL

1. Reason for the Job
To set the clearances of the MLG downlock proximity sensors to the correct dimensions.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT)
No specific	1	CONTAINER - CLEAN, APPLICABLE
No specific	AR	POWER SUPPLY UNIT 24V/10A-DC
No specific	AR	SAFETY BARRIER(S)
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.192 and 0.124 m.daN (16.99 and 10.97 lbf.in )
No specific	Torque wrench: range to between 1.6 and 1.5 m.daN (11.80 and 11.06 lbf.ft )
No specific	Torque wrench: range to between 2.8 and 2.4 m.daN (20.65 and 17.70 lbf.ft )
460005832	1	SPRING EXPANDER-MLG SIDE STAY
460005835	1	SLEEVE - GROUND LOCK
460005842	1	LAMP BOX
460006428	1	BLOCK - SETTING
460006429	1	SETTING BLOCK
460007262	1	GAUGE - CHECKING

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.10ABC1)	Surface Pretreatment-Light Alloys Chemical Conversion Yellow -
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -

C. Referenced Information

REFERENCE	DESIGNATION
TASK 07-11-00-581-001-A	Lifting for Aircraft Maintenance Operations
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 29-10-00-864-001-A	Depressurize the Green Hydraulic System
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 29-23-00-860-001-A	Disconnection of the Isolation Coupling of the Power Transfer Unit (PTU)
TASK 29-23-00-860-002-A	Connection of the Isolation Coupling of the Power Transfer Unit (PTU)
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 32-00-00-860-002-A	Ground Configuration after Flight Configuration with Electrical Power
TASK 32-00-00-860-002-A-01	Ground Configuration after Flight Configuration without Electrical Power
TASK 32-11-19-000-001-A	Removal of the MLG Lock Springs
TASK 32-11-19-400-001-A	Installation of the MLG Lock Springs
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
TASK 32-69-00-740-001-A	BITE Check of Landing-Gear Control Interface-Unit (LGCIU) With Use of MCDU to Ensure that Continuous BITE is Operative
Adjustment MLG Downlock Proximity Sensors 14GA, 15GA, 16GA, 17GA
MLG Lock-stay Actuator Hydraulic Pipe - Details
Proximity-Sensor Adjustment Dimensions 14GA, 15GA, 16GA, 17GA
Check of the MLG Lockstay Over Center Position

3. Job Set-up
Subtask 32-31-73-941-058-A

A. Safety Precautions
(1) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(2) Make sure that the ground safety locks are installed on the landing gear (Ref. AMM TASK 32-00-00-481-001).
(3) On panel 400VU:

Make sure that the landing-gear control-lever 6GA is in the DOWN position
Put a WARNING NOTICE(S) in position to tell persons not to operate the landing gear and the MLG doors.

Subtask 32-31-73-860-057-A

B. Aircraft Maintenance Configuration
(1) Make sure that the Green hydraulic system is depressurized (Ref. AMM TASK 29-10-00-864-001).
(2) Depressurize the applicable hydraulic reservoir (Ref. AMM TASK 29-14-00-614-001).
(3) Disconnect the isolation coupling of the PTU (Ref. AMM TASK 29-23-00-860-001).
(4) 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 open the LGCIU circuit breakers.
(5) If the electrical power is necessary, do the precautions for flight configuration with electrical power before you open the circuit breakers (Ref. AMM TASK 32-00-00-860-001).

Subtask 32-31-73-582-055-A

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

Subtask 32-31-73-865-069-A

D. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	L/G/LGCIU/SYS1/NORM	1GA	C09
** ON A/C NOT FOR ALL
121VU	LGCIU/BAT SPLY/SYS2	59GA	R33
121VU	LGCIU/BAT SPLY/SYS1	58GA	R32
** ON A/C ALL
121VU	HYDRAULIC/LGCIU/SYS2	2GA	Q35
121VU	HYDRAULIC/LGCIU/SYS1/GRND SPLY	52GA	Q34
** ON A/C NOT FOR ALL
121VU	LGCIU/BAT SPLY/SYS2	59GA	R32
121VU	LGCIU/BAT SPLY/SYS1	58GA	R31

Subtask 32-31-73-010-055-A

E. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position below the applicable zone 734(744).
(2) Open the applicable MLG door (Ref. AMM TASK 32-12-00-010-001).
(3) Make sure that the 460005835 SLEEVE - GROUND LOCK is on the applicable MLG door actuator (Ref. AMM TASK 32-00-00-481-002).

4. Procedure
Subtask 32-31-73-220-079-A

A. Dimensional Check

Adjustment MLG Downlock Proximity Sensors 14GA, 15GA, 16GA, 17GA

NOTE: For the dimensions 'new' and 'in service', you must refer to the list that follows:

When the two interface components are new, you must refer to the new dimensions
When one interface component is new and the other component is in service, you must refer to the in service dimensions
When the two interface components are in service, you must refer to the in service dimensions.
'New' refers to a component not used since it was made.
'In service' refers to a component that has been overhauled or used since it was made.

(1) For the MLG downlock proximity sensors 15GA(14GA), measure the clearances as follows:
(a) For a new MLG lockstay or sidestay:
1 Measure the dimension Z:

Make sure it is between 1.4 mm (0.0551 in.) and 1.6 mm (0.0630 in.).

2 Measure the dimension X:

Make sure that it is between 0.7 mm (0.0276 in.) and 0.9 mm (0.0354 in.).

(b) For an in service MLG lockstay or sidestay:
1 Measure the dimension Z:

Make sure that it is between 0.6 mm (0.0236 in.) and 2.4 mm (0.0945 in.).

2 Measure the dimension X:

Make sure that it is between 0.35 mm (0.0138 in.) and 1.25 mm (0.0492 in.).

(2) For the MLG downlock proximity sensors 17GA(16GA), measure the clearances as follows:
(a) For a new MLG lockstay or sidestay:
1 Measure the dimension Z:

Make sure that it is between 1.4 mm (0.0551 in.) and 1.6 mm (0.0630 in.).

2 Measure the dimension X:

Make sure that it is between 2.4 mm (0.0945 in.) and 2.6 mm (0.1024 in.).

(b) For an in service lockstay or sidestay:
1 Measure the dimension Z:

Make sure that it is between 1.05 mm (0.0413 in.) and 1.95 mm (0.0768 in.).

2 Measure the dimension X:

Make sure that it is between 2.2 mm (0.0866 in.) and 2.8 mm (0.1102 in.).

(3) If the dimensions are correct, do the check of the proximity switch detection range in Para 4.B.
(4) If the dimensions are incorrect, do the adjustment procedure in Para 4.C., then do the check of the proximity switch detection range in Para 4.B.

Subtask 32-31-73-220-080-A

B. Check of the Proximity Switch Detection Range
(1) Install the 460005832 SPRING EXPANDER-MLG SIDE STAY on the applicable MLG lock springs.
(2) Remove the applicable MLG lock springs (Ref. AMM TASK 32-11-19-000-001).

MLG Lock-stay Actuator Hydraulic Pipe - Details

(3) Put a CONTAINER - CLEAN, APPLICABLE in position under the hydraulic unions (20) and (21).
(4) Release the hydraulic unions (20) and (21) to decrease the hydraulic pressure in the lockstay actuator.
(5) Remove the ground lock sleeve from the applicable MLG lockstay actuator.
(6) Install the 460007262 GAUGE - CHECKING on the applicable lockstay actuator as follows:
(a) Install the checking gage upper attachment pin in the lockstay actuator upper attachment point.
(b) Install the checking gage lower attachment pin through the hole mark 30 on the checking gage.
(c) Make sure that the lower attachment pin engages correctly in the lockstay actuator lower attachment point.
(7) Disconnect the electrical cable from the applicable proximity sensor.
(8) Connect the 460005842 LAMP BOX to the electrical connector of the applicable proximity sensor.
(9) Connect a POWER SUPPLY UNIT 24V/10A-DC to the lamp box and put the power switch to ON.
(10) Make sure that the RED lamp on the lamp box is ON.
(11) Set the applicable outlet cable indicator switch on the LAMP BOX to ON.
(12) Make sure that the GREEN lamp on the lamp box is ON.
(13) Remove the lower attachment pin from the checking gage.
(14) Manually move the lockstay away from the locked down position.
(15) Continue to move the lockstay until the lower attachment pin can be engaged in the hole mark 20 on the checking gage. The GREEN lamp must not go OFF.
(16) Remove the lower attachment pin from the hole mark 20 on the checking gage.
(17) Move the lockstay until the lower attachment pin can be engaged in the hole mark 10 on the checking gage. The GREEN lamp must go OFF.
(18) Remove the pin from the hole mark 10 on the checking gage.
(19) Move the lockstay towards the locked down position.
(20) The GREEN lamp on the lamp box must come ON before the pin can be engaged in the hole mark 20 on the checking gage.
(21) Remove the pin and continue to move the lockstay to the locked down position.
(22) Engage the pin in the hole mark 30. Make sure that the GREEN lamp on the lamp box stays ON.
(23) Do the steps (13) to (22) one more time.
(24) Set the lamp box switches to OFF.
(25) Install the ground lock sleeve on the applicable MLG lockstay actuator (Ref. AMM TASK 32-00-00-481-001).
(26) Remove the 460005842 LAMP BOX from the applicable proximity sensor.
(27) Connect the electrical cable to the applicable proximity sensor.
(28) Remove the 460007262 GAUGE - CHECKING from the applicable lockstay actuator.
(29) Install the applicable MLG lock springs (Ref. AMM TASK 32-11-19-400-001).
(30) Tighten the hydraulic unions (20) and (21).
(a) Torque the hydraulic union (20) to between 2.8 and 2.4 m.daN (20.65 and 17.70 lbf.ft )

.
(b) Torque the hydraulic union (21) to between 1.6 and 1.5 m.daN (11.80 and 11.06 lbf.ft )

Subtask 32-31-73-820-050-A

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

C. Adjustment of the MLG Downlock Proximity Sensors 14GA, 15GA (System 1) and 16GA, 17GA (System 2)

NOTE: If the calculated clearance between the target and the sensor is correct, you can install a sensor target without a spacer.

(1) If dimension Z at proximity sensor 15GA(14GA) is incorrect, do the steps that follow:
(a) Remove and discard the lockwire from the cap-screws (6).
(b) Remove the cap-screws (6) and the washers (5).
(c) Remove the bracket (7) and the spacers (4) (if installed).
(d) Make sure that the bracket (7) is in the correct condition.
(e) If necessary, machine the faces of the spacers (4) to get correct dimension Z.
(f) If it is necessary to install the spacers (4), apply Surface Pretreatment-Light Alloys Chemical Conversion Yellow - (Material No.10ABC1) to the faces of the spacers (4).
(g) Install the bracket (7) (and if necessary, the spacers (4)) with the cap-screws (6) and the washers (5).
(h) TORQUE the cap-screws (6) to between 0.192 and 0.124 m.daN (16.99 and 10.97 lbf.in )

.
(i) Safety the cap-screws (6) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(2) If dimension X at the proximity sensor 15GA(14GA) is incorrect, do the steps that follow:
(a) Remove the nuts (8), washers (9) and screws (1).
(b) Remove the target (2) and the spacer (3) (if installed).
(c) Make sure that the bracket (7) is in the correct condition.
(d) Install the 460006428 BLOCK - SETTING on the bracket (7).

Proximity-Sensor Adjustment Dimensions 14GA, 15GA, 16GA, 17GA

(e) If it is necessary to install the spacer (3), calculate its thickness (dimension E) as follows:
1 Measure and record dimensions F, G and H.
2 Calculate dimension J (J = Dimension G - 7.450 mm (0.2933 in.)).
3 Measure and record dimension K.
4 The thickness of the spacer (17) (dimension E) = F - (H + J + K).
(f) If necessary, machine the faces of the spacer (3) to get correct dimension X.
(g) Remove the 460006428 BLOCK - SETTING from the bracket (7).
(h) If it is necessary to install the spacer (3), apply Surface Pretreatment-Light Alloys Chemical Conversion Yellow - (Material No.10ABC1) to the faces of the spacer.
(i) Install the target (2) (and if necessary, the spacer (3)), with the screws (1), washers (9) and nuts (8).
(3) If dimension Z at proximity sensor 17GA(16GA) is incorrect, do the steps that follow:
(a) Remove the cap-screws (16), washers (11) and nuts (10).
(b) Remove the adaptor (13) and the spacer (12) (if installed).
(c) Make sure that the target mounting bracket is in the correct condition.
(d) If necessary, machine the faces of the spacer (12) to get correct dimension Z.
(e) If it is necessary to install the spacer (12), apply Surface Pretreatment-Light Alloys Chemical Conversion Yellow - (Material No.10ABC1) to the faces of the spacer (12).
(f) Install the spacer (12) (if necessary), adaptor (13), cap-screws (16), washers (11) and nuts (10).
(4) If dimension X at proximity sensor 17GA(16GA) is incorrect, do the steps that follow:
(a) Remove the cap-screws (19), washers (15) and nuts (14).
(b) Remove the target (18) and the spacer (17) (if installed).
(c) Make sure that the target mounting bracket is in the correct condition.
(d) Install the 460006429 SETTING BLOCK on the adaptor (13).
(e) If it is necessary to install the spacer (17), calculate its thickness (dimension L) as follows:
1 Measure and record dimensions N, P and Q.
2 Calculate dimension M (M = Q + 5.75 mm (0.2264 in.)).
3 The thickness of the spacer (17) (dimension L) = M - (N + P).
(f) If necessary, machine the faces of the spacer (17) to get correct dimension X.
(g) Remove the 460006428 BLOCK - SETTING from the adaptor (13).
(h) If it is necessary to install the spacer (17), apply Surface Pretreatment-Light Alloys Chemical Conversion Yellow - (Material No.10ABC1) to the faces of the spacer (17).
(i) Install the target (18) (and if necessary, the spacer (17)) with the cap-screws (19), washers (15) and nuts (14).

Subtask 32-31-73-865-070-A

D. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	L/G/LGCIU/SYS1/NORM	1GA	C09
** ON A/C NOT FOR ALL
121VU	LGCIU/BAT SPLY/SYS2	59GA	R33
121VU	LGCIU/BAT SPLY/SYS1	58GA	R32
** ON A/C ALL
121VU	HYDRAULIC/LGCIU/SYS2	2GA	Q35
121VU	HYDRAULIC/LGCIU/SYS1/GRND SPLY	52GA	Q34
** ON A/C NOT FOR ALL
121VU	LGCIU/BAT SPLY/SYS2	59GA	R32
121VU	LGCIU/BAT SPLY/SYS1	58GA	R31

Subtask 32-31-73-740-057-A

E. Test
(1) Do a BITE test of the landing gear (Ref. AMM TASK 32-69-00-740-001).

Subtask 32-31-73-582-056-A

F. Lower the Aircraft
(1) Lower the aircraft off jacks (Ref. AMM TASK 07-11-00-586-002).

Subtask 32-31-73-860-058-A

G. Aircraft Maintenance Configuration
(1) If you did the flight configuration precautions, put the aircraft back to the ground configuration (Ref. AMM TASK 32-00-00-860-002).
(2) Connect the isolation coupling of the PTU (Ref. AMM TASK 29-23-00-860-002).
(3) Pressurize the applicable hydraulic reservoirs (Ref. AMM TASK 29-14-00-614-002).

Subtask 32-31-73-410-056-A

H. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the access platform(s).
(3) Close the MLG doors (Ref. AMM TASK 32-12-00-410-001).

5. Close-up
Subtask 32-31-73-942-057-A

A. Removal of 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] 2026.04.01 12:31:13 UTC