L/G Downlock Proximity Sensor TGT POS Fault (sensors 14GA thru 19GA)

TASK 32-31-00-810-896-A
L/G Downlock Proximity Sensor TGT POS Fault (sensors 14GA thru 19GA)

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. MOVEMENT OF THE LANDING GEAR CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

1. Possible Causes

L/G Slow To Operate
Aircraft wiring

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

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 32-31-00-810-862-A	NLG Does Not Downlock
TSM TASK 32-31-00-810-863-A	MLG (LH) Does Not Downlock
TSM TASK 32-31-00-810-864-A	MLG (RH) Does Not Downlock
AMM 29-00-00-864-001	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
AMM 32-00-00-860-001	Flight Configuration Precautions with Electrical Power
ASM 323103
ASM 323104
AMM 32-31-71-000-001	Removal of the LGCIU
AMM 32-31-71-400-001	Installation of the LGCIU
AMM 32-31-73-000-001	Removal of the MLG Proximity-Sensors
AMM 32-31-73-000-005	Removal of the NLG Proximity-Sensors
AMM 32-31-73-200-001	Inspection of the MLG Proximity Sensor and Target Clearances
AMM 32-31-73-200-002	Inspection of the NLG Proximity Sensor and Target Clearances
AMM 32-31-73-400-001	Installation of the MLG Proximity-Sensors
AMM 32-31-73-400-005	Installation of the NLG Proximity-Sensors
AMM 32-31-73-820-008	Inductance Check of the Proximity Sensors/Switches
AMM 32-31-73-820-009	Resistance Check of the Proximity Sensors
AMM 32-69-00-740-001	BITE Check of Landing-Gear Control Interface-Unit (LGCIU) With Use of MCDU to Ensure that Continuous BITE is Operative

3. Fault Confirmation
Subtask 32-31-00-700-057-B

A. Message Analysis
(1) If a L/G DNLK PROX SNSR TGT POS fault is shown on the Post Flight Report (PFR) on a set of sensors at the same time (+/- 1 minute), then the fault can be caused by L/G Slow To Operate. In this condition, do the trouble shooting as follows:

For NLG Door Open Sensors (18GA and 19GA) do (Ref. TSM TASK 32-31-00-810-862)
for LH MLG Door Open Sensors (15GA and 17GA) do (Ref. TSM TASK 32-31-00-810-863)
for RH MLG Downlock Sensors (14GA and 16GA) do (Ref. TSM TASK 32-31-00-810-864).

(2) Do the flight configuration precautions AMM 32-00-00-860-001, and make sure that all the aircraft systems are in the ground configuration.
(3) Make sure that the Green and Yellow Hydraulic systems are depressurized and put in the maintenance configuration AMM 29-00-00-864-001.
(4) Open the circuit breaker(s) to stop the supply to the LGCIU in the opposite system to the proximity sensor shown on the PFR:
(a) For FINS 14GA, 15GA or 18GA:

Open, safety and tag this(these) circuit breaker(s):
2GA and 59GA to make sure that only the LGCIU 1 indication shows on the ECAM wheel page.

(b) For FINS 16GA, 17GA or 19GA:

Open, safety and tag this(these) circuit breaker(s):
1GA, 52GA and 58GA to make sure that only the LGCIU 2 indication shows on the ECAM wheel page.

(5) At the ECAM Control Page, select the WHEEL page:
(a) At the lower ECAM DU, on the wheel page:

Make sure that all the L/G symbols show as a green triangle. If the system has failed, the L/G symbols will show as two amber crosses.

1 If the triangles for the applicable L/G are shown as red or amber crosses, go to Para. Fault Isolation.
2 If the applicable L/G symbols are shown as a green triangle, do the next step (6).
(6) Close this(these) circuit breaker(s):

1GA, 2GA and 52GA.

(7) Put the aircraft back to its initial configuration.
(8) Do a BITE test on the LGCIU 1 or LGCIU 2 AMM 32-69-00-740-001.
(a) If the test is OK:

Go to Para. Fault Isolation.

(b) If the test(s) give(s) a fault message.

Do the related trouble Shooting procedure.

NOTE: The L/G DNLK PROX SNSR TGT POS faults cannot be identified with the BITE TEST, but other related faults can be found. Target position faults can be confirmed by continuous monitoring (BITE) during L/G operation. To confirm a target position fault, it is necessary to do the proximity-sensor/target inspection, the inductance and the resistance checks, given in the Para. Fault Isolation.

4. Fault Isolation
Subtask 32-31-00-810-158-A

A. Procedure
(1) Do the inspection of the applicable L/G proximity sensor, related to the fault message, and adjust as necessary.
(a) For the MLG proximity sensor Faults (14GA, 15GA, 16GA OR 17GA) do the inspection of the MLG Proximity Sensor and Target Clearances AMM 32-31-73-200-001.
(b) For the NLG proximity sensor faults (18GA or 19GA), do the Inspection of the NLG Proximity Sensor and Target Clearances AMM 32-31-73-200-002.
(c) Do the test(s) given in the Para. Fault Confirmation.
(2) Do a check of the resistance of the applicable proximity sensor AMM 32-31-73-820-009:

if the resistance values are correct, do the next step
if one or more of the resistance values is not correct, do the step (4).

(3) Do the check of the inductance of the applicable proximity sensor AMM 32-31-73-820-008:

if the inductance is correct, do the Para. 4.B
if the inductance is not correct, do the next step.

(4) Replace the applicable Proximity Sensor:
(a) For the NLG Proximity Sensor AMM 32-31-73-000-005 and AMM 32-31-73-400-005.
(b) For the MLG Proximity Sensor AMM 32-31-73-000-001 and AMM 32-31-73-400-001.
(c) Do the test(s) given in the Para. Fault Confirmation.
(5) Do a check of the inductance of the new replacement sensor sensor AMM 32-31-73-820-008:

if the inductance is correct, no more maintenance work is necessary
if the inductance is not correct, do the next step.

Subtask 32-31-00-810-159-A

B. If the fault continues:
(1) Interchange the LGCIU-1 and LGCIU-2, AMM 32-31-71-000-001 and AMM 32-31-71-400-001.
(a) If the fault moves:
1 Interchange the LGCIU-1 AND LGCIU-2 back and replace the defective LGCIU-1 (5GA1) or LGCIU-2 (5GA2), AMM 32-31-71-000-001 and AMM 32-31-71-400-001.
2 Do the test(s) given in the Para. Fault Confirmation.
(b) If the fault does not move to the other LGCIU position:

Do the next step.

(2) Do a check of and repair as necessary the Aircraft wiring between the:

electrical connectors on the applicable proximity sensor and related LGCIU ARINC tray ASM 323103 or ASM 323104.

(3) If the fault continues do the next step.

NOTE: For intermittent faults it may be necessary to gently shake the wiring harnesses when performing the above wiring checks.

(4) Do the test(s) given in the Para. Fault Confirmation.

5. Close-up
Subtask 32-31-00-942-066-A

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:31:27 UTC