Disagree between LGCIU1 and LGCIU2 for the SEC

TASK 27-94-00-810-894-A
Disagree between LGCIU1 and LGCIU2 for the SEC

1. Possible Causes

SEC-3 [1CE3]
SEC-2 [1CE2]
SEC-1 [1CE1]
LGCIU-1 [5GA1]
LGCIU-2 [5GA2]
PROX SNSR-R L/G EXT, SYS 1 [20GA]
PROX SNSR-L L/G EXT, SYS 1 [21GA]
PROX SNSR-R L/G EXT, SYS 2 [22GA]
PROX SNSR-L L/G EXT, SYS 2 [23GA]
PROX SNSR-NLG UPLK, SYS 1 [12GA]
PROX SNSR-NLG UPLK, SYS 2 [13GA]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)
AMM 32-00-00-860-002	Ground Configuration after Flight Configuration with Electrical Power
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
AMM 32-69-00-860-001	Simulation of Flight (With Aircraft on Ground)

3. Fault Confirmation
Subtask 27-94-00-860-077-A

A. Test
(1) Do the simulation of flight, with the aircraft on the ground AMM 32-69-00-860-001.

Subtask 27-94-00-740-156-A

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

4. Fault Isolation
Subtask 27-94-00-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FLIGHT CONTROLS/SEC1/NORM/SPLY	21CE1	B08
105VU	FLT CTL/SEC1/STBY SPLY	22CE	B01
121VU	FLIGHT CONTROLS/SEC3/SPLY	21CE3	Q19
121VU	FLIGHT CONTROLS/SEC2/SPLY	21CE2	Q18

Subtask 27-94-00-810-145-A

B. If the test doesn' t confirm the fault and if the maintenance message LGCIU BUS DISAGREE was shown after landing gear free-fall extension:

no maintenance action is necessary.

Subtask 27-94-00-810-131-A

C. If the BITE test gives the maintenance message:
LGCIU BUS DISAGREE

open the circuit breaker (21CE1) on the panel 49VU and the circuit breaker (22CE) on the panel 105VU for the SEC1
open the circuit breaker (21CE2) on the panel 121VU for the SEC2 and do the test given in Para. 3. (only the SEC3 is supplied).

(1) Close the circuit breaker (21CE2).
(2) Open the circuit breaker (21CE3) on the panel 121VU for the SEC3 and do the test given in Para. 3. (only the SEC2 is supplied).
(3) Close the circuit breakers (21CE1) and (22CE).
(4) Open the circuit breaker (21CE2) on the panel 121VU for the SEC2 and do the test given in Para. 3. (only the SEC1 is supplied).
(5) Close the circuit breakers (21CE2) and (21CE3).
(a) If the message is shown only when the SEC3 is supplied:

replace the SEC-3 [1CE3] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

(b) If the message is shown only when the SEC2 is supplied:

replace the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

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:

replace the LGCIU-2 [5GA2] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

(d) If the message is shown when the SEC2 is supplied and when the SEC3 is supplied:

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

1 If the fault continues:

replace the LGCIU-2 [5GA2] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

(e) If the message is shown when the SEC1 is supplied, when the SEC2 is supplied and when the SEC3 is supplied:

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

1 If the fault continues:

replace the LGCIU-2 [5GA2] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

2 If the fault continues:

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

3 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.

4 If the fault continues:

replace the PROX SNSR-R L/G EXT, SYS 2 [22GA] AMM 32-31-73-000-001, AMM 32-31-73-400-001.

5 If the fault continues:

replace the PROX SNSR-L L/G EXT, SYS 2 [23GA] AMM 32-31-73-000-001, AMM 32-31-73-400-001.

6 If the fault continues:

replace the PROX SNSR-NLG UPLK, SYS 1 [12GA] AMM 32-31-73-000-005, AMM 32-31-73-400-005.

7 If the fault continues:

replace the PROX SNSR-NLG UPLK, SYS 2 [13GA] AMM 32-31-73-000-005, AMM 32-31-73-400-005.

Subtask 27-94-00-740-157-A

D. Do the test given in Para. 3.

5. Close-up
Subtask 27-94-00-860-078-A

A. Do the ground configuration after the flight configuration AMM 32-00-00-860-002.

[Rev.8 from Aug 2018] 2026.04.04 04:28:20 UTC