Loss of the LGCIU 1 Discrete Inputs for the ELAC

TASK 27-93-00-810-921-A
Loss of the LGCIU 1 Discrete Inputs for the ELAC

1. Possible Causes

PROX SNSR-R L/G EXT, SYS 1 [20GA]
PROX SNSR-L L/G EXT, SYS 1 [21GA]
PROX SNSR-NLG EXT, SYS 1 [24GA]
ELAC-2 [2CE2]
LGCIU-1 [5GA1]
wiring from the ELAC 2 (2CE2) to the LGCIU 1 (5GA1)
ELAC-1 [2CE1]
wiring from the ELAC 1 (2CE1) to the LGCIU 1 (5GA1)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 279243
AMM 27-93-34-000-001	Removal of the ELAC
AMM 27-93-34-400-001	Installation of the ELAC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)
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 32-31-73-400-001	Installation of the MLG Proximity-Sensors
AMM 32-31-73-400-005	Installation of the NLG Proximity-Sensors

3. Fault Confirmation
Subtask 27-93-00-740-162-A

A. Test
(1) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.

4. Fault Isolation
Subtask 27-93-00-865-051-A

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FLIGHT CONTROLS/ELAC1/NORM/SPLY	15CE1	B11
105VU	FLIGHT CONTROLS/ELAC2/STBY SPLY	16CE2	A02
105VU	FLT CTL/ELAC1/STBY SPLY	16CE1	A01
121VU	FLIGHT CONTROLS/ELAC2/NORM/SPLY	15CE2	R20

Subtask 27-93-00-810-219-A

B. If the test doesn't confirm the fault or if the maintenance message CHECK LGCIU1 DISC INPUTS was shown after landing gear free-fall extension:

no maintenance action is necessary.

Subtask 27-93-00-810-155-A

C. If the BITE test gives the maintenance message:
CHECK LGCIU1 DISC INPUTS

replace the PROX SNSR-R L/G EXT, SYS 1 [20GA] AMM 32-31-73-000-001 and AMM 32-31-73-400-001.

(1) If the fault continues:

replace the PROX SNSR-L L/G EXT, SYS 1 [21GA] AMM 32-31-73-000-001 AMM 32-31-73-400-001.

(2) If the fault continues:

replace the PROX SNSR-NLG EXT, SYS 1 [24GA] AMM 32-31-73-000-005 AMM 32-31-73-400-005.

(3) If the fault continues:

open the circuit breaker (15CE1) on the panel 49VU and the circuit breaker (16CE1) on the panel 105VU and do the test given in Para. 3.

(4) Close the circuit breakers (15CE1) and (16CE1).
(5) Open the circuit breaker (15CE2) on the panel 121VU and the circuit breaker (16CE2) on the panel 105VU and do the test given in Para. 3.
(6) Close the circuit breakers (15CE2) and (16CE2).
(a) If the message is shown only when the circuit breakers (15CE1) and (16CE1) are open:

replace the ELAC-2 [2CE2] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.

1 If the fault continues:

replace the LGCIU-1 [5GA1] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

2 If the fault continues:

do a check and repair the wiring from the ELAC 2 (2CE2) to the LGCIU 1 (5GA1) ASM 279243.

(b) If the message is shown only when the circuit breakers (15CE2) and (16CE2) are open:

replace the ELAC-1 [2CE1] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.

1 If the fault continues:

replace the LGCIU-1 [5GA1] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

2 If the fault continues:

do a check and repair the wiring from the ELAC 1 (2CE1) to the LGCIU 1 (5GA1) ASM 279243.

(c) If the message is shown when the circuit breakers (15CE1), (16CE1) are open then, when the circuit breakers (15CE2), (16CE2) are open:

replace the LGCIU-1 [5GA1] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

Subtask 27-93-00-740-163-A

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:28:06 UTC