W DOC AIRBUS | TSM A320F

L/G Shock Absorber Extended Proximity Sensor TGT POS Fault (20GA thru 25GA)

TASK 32-31-00-810-842-A
L/G Shock Absorber Extended Proximity Sensor TGT POS Fault (20GA thru 25GA)

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
  • target lever, rod links and attachment bolts
  • shock-absorber proximity-sensor
  • LGCIU-1 [5GA1]
  • LGCIU-2 [5GA2]
  • aircraft wiring
  • Nose Landing Gear Upper Support Anti-rotation Lugs.
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 32-31-00-810-868-A
NLG Shock Absorber Does Not Extend (L/G will not retract)
TSM TASK 32-31-00-810-869-A
MLG (LH) Shock Absorber Does Not Extend
TSM TASK 32-31-00-810-870-A
MLG (RH) Shock Absorber Does Not Extend
TSM TASK 32-31-00-810-885-A
L/G - Lever Does Not Move - Retraction Inhibit Baulk Solenoid Does Not Release
AMM 32-21-00-200-008
Borescope Inspection of the Nose Landing Gear Upper-Support Anti-Rotation lugs and Cylinder lugs
AMM 32-31-00-720-002
Functional Test of the Normal Extension and Retraction of the Landing Gear
AMM 32-31-00-720-003
Functional Test of the Normal Extension and Retraction of the Nose Landing Gear
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
3. Fault Confirmation
Subtask 32-31-00-710-060-A
A. Test
   (1) If a shock-absorber proximity-sensor (20GA thru 25GA) target position message is shown on the Post Flight Report (PFR), do the applicable functional test of the Main L/G AMM 32-31-00-720-002, or Nose L/G AMM 32-31-00-720-003:
  • if the initial test is OK, continue and do the inductance check in Para. 4.A., for all the shock-absorber proximity-sensors
  • if during the initial test, the L/G control lever does not move to the UP position, do the fault isolation procedures in Para. 4.A., then do the trouble shooting for the L/G control-lever baulk-solenoid (Ref. TSM TASK 32-31-00-810-885)
  • if a subsequent test is OK, after the fault isolation procedure(s) is done, no more maintenance work is necessary.
NOTE: If the L/G lever does not move to the UP position there are two faults, one in System 1 and one in System 2. If the shock-absorber proximity-sensors are serviceable and the L/G lever does not move, then the two faults are in the L/G lever unit, or the LGCIU, or the related aircraft wiring. If one of the two faults goes, the L/G lever will operate correctly, but the fault in the opposite system stays. Thus it is also necessary to do the L/G lever trouble shooting task to find the other fault.
NOTE: The Fault Confirmation that follows is only applicable to LGCIU part number 80-178-02-8812.
   (2) If one or more of the messages that follow are shown during ground maintenance, do the applicable trouble shooting procedure:
4. Fault Isolation
Subtask 32-31-00-810-094-A ** ON A/C NOT FOR ALL
A. Procedure
   (1) For the applicable proximity sensor shown on the Post Flight Report (PFR), do the inspection of the clearance between the proximity-sensor and its target, AMM 32-31-73-200-001 or AMM 32-31-73-200-002:
     (a) On the NLG shock absorber proximity sensors (24GA, 25GA) and the related NLG flight and ground sensing mechanism:
       1 Make sure that the target lever, rod links and attachment bolts are correctly installed.
  • If the target lever, rod links or attachment bolts are repaired or replaced, do the step (2)
  • If a clearance is adjusted, do the step (2)
  • If the clearance is correct, do the step (3).
   (2) Do the test in Para. 3.A.:
  • If the fault continues, do the step (3).
   (3) 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 (5).
   (4) Do an inductance check of the applicable proximity sensors, AMM 32-31-73-820-008:
  • If the inductances are correct, do the step (7)
  • If an inductance is not correct, do the next step.
   (5) Replace the unserviceable shock-absorber proximity-sensor :
   (6) Do a check of the inductance of the new replacement 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.
     (a) Do the test in Para. 3.A.:
  • If the fault continues, do the step (7).
   (7) Replace the applicable LGCIU-1 [5GA1] or LGCIU-2 [5GA2] , AMM 32-31-71-000-001 and AMM 32-31-71-400-001.
     (a) Do the test in Para. 3.A.:
  • If the fault continues, do the step (8).
   (8) Do a check and repair as necessary the aircraft wiring between the applicable proximity sensor and the related LGCIU.
     (a) Do the test in Para. 3.A.
Subtask 32-31-00-810-094-B ** ON A/C NOT FOR ALL
A. Procedure
   (1) Before you do this procedure you must refer to (Ref. SB 32-1310) Inspection of the Nose Landing Gear Upper Support. This is necessary to make sure that the inspection is applicable.
NOTE: For aircraft that have BSCU STD.L4.8 or a non EMM BSCU STD. No borescope inspection is necessary if:
  • A NLG with new upper support anti-rotation lugs, and new cylinder lugs is installed
    Or
  • A NLG which has not been controlled by an EMM BSCU L4.1 or L4.5 is installed.
   (2) If applicable do the Borescope Inspection of the Nose Landing Gear Upper Support Anti-rotation Lugs. , AMM 32-21-00-200-008.
NOTE: The borescope inspection task must be done when the CFDS MESSAGE " N L/G EXT PROX SNSR 24GA TGT POS" and/or "N L/G EXT PROX SNSR 25GA TGT POS" is shown. The borescope inspection can be done the next time at the main base, but must be done before one hundred (100) flight cycles.
   (3) For the applicable proximity sensor shown on the Post Flight Report (PFR), do the inspection of the clearance between the proximity-sensor and its target, AMM 32-31-73-200-001 or AMM 32-31-73-200-002:
     (a) On the NLG shock absorber proximity sensors (24GA, 25GA) and the related NLG flight and ground sensing mechanism:
       1 Make sure that the target lever, rod links and attachment bolts are correctly installed.
  • If the target lever, rod links or attachment bolts are repaired or replaced, do the step (4)
  • If a clearance is adjusted, do the step (4)
  • If the clearance is correct, do the step (5).
   (4) Do the test in Para. 3.A.:
  • If the fault continues, do the step (5).
   (5) 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 (7).
   (6) Do an inductance check of the applicable proximity sensors, AMM 32-31-73-820-008:
  • If the inductances are correct, do the step (9)
  • If an inductance is not correct, do the next step.
   (7) Replace the unserviceable shock-absorber proximity-sensor :
     (a) Do the test in Para. 3.A.:
  • If the fault continues, do the next step.
   (8) Do a check of the inductance of the new replacement 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.
   (9) Replace the applicable LGCIU-1 [5GA1] or LGCIU-2 [5GA2] , AMM 32-31-71-000-001 and AMM 32-31-71-400-001.
     (a) Do the test in Para. 3.A.:
  • If the fault continues, do next step.
   (10) Do a check and repair as necessary the aircraft wiring between the applicable proximity sensor and the related LGCIU.
     (a) Do the test in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:31:23 UTC
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