Loss of the THS Command Transducer Signal for the ELAC 2

TASK 27-93-00-810-833-A
Loss of the THS Command Transducer Signal for the ELAC 2

1. Possible Causes

ELAC-2 [2CE2]
command position transducer
wiring of the XDCR COM SPLY signal from the THS actuator (9CE) to the first terminal block
wiring of the XDCR COM V1, V2 signals from the THS actuator (9CE) to the ELAC 2 (2CE2)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 27-90-00-810-814-A	Loss of the ACS1 Signal of the ELAC2 COM Side
TSM TASK 27-90-00-810-815-A	Loss of the ACS1 Signal of the ELAC2 MON Side
TSM TASK 27-90-00-810-816-A	Loss of the ACS1 of the ELAC2 COM and MON Sides
TSM TASK 27-90-00-810-823-A	Loss of the ACS1 Signal of the ELAC2 COM Side and SEC2 COM Side
AMM 27-44-56-000-001	Removal of the Position Transducer from the THS Actuator
AMM 27-44-56-400-001	Installation of the Position Transducer to the THS Actuator
ASM 279313
AMM 27-93-34-000-001	Removal of the ELAC
AMM 27-93-34-400-001	Installation of the ELAC
AMM 27-96-00-710-022	Operational Test of the THS Actuator Electrical Control (Activation for BITE Test)
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)

3. Fault Confirmation
Subtask 27-93-00-700-078-A

A. Test
(1) Do the operational test of the THS actuator electrical control AMM 27-96-00-710-022.

NOTE: Do the ground setting only with the ELAC 2.

(2) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.
(a) If the ground scanning gives the maintenance message:
ELAC2 COM OR INPUT OF THS ACTR XDCR1 9CE

refer to Para. Fault Isolation.

(b) If the ground scanning gives at least two maintenance messages of the two lists below:
First list:

ELAC2 COM OR INPUT OF THS ACTR XDCR1 9CE
ELAC2 OR WIRING FROM L G ELEV POS XDCR 34CE1
ELAC2 OR WIRING FROM R Y ELEV POS XDCR 34CE2
Second list:
ELAC2 MON OR INPUT OF THS ACTR XDCR1 9CE
ELAC2 OR WIRING FROM L ELEV POS MON XDCR
ELAC2 OR WIRING FROM R ELEV POS MON XDCR
ELAC2 OR WIRING FROM L B ELEV MODE XDCR 34CE3
ELAC2 OR WIRING FROM R Y ELEV MODE XDCR 34CE4

1 First case:
Combination of maintenance messages of the first list, do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-814).
2 Second case:
Combination of maintenance messages of the second list, do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-815).
3 Third case:
Combination of maintenance messages of the first and second lists, do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-816).
(c) If the ground scanning gives at least two maintenance messages of the list below:
ELAC2 COM OR INPUT OF THS ACTR XDCR1 9CE
SEC2 COM OR INPUT OF THS ACTR XDCR3 9CE
L G ELEV MODE XDCR 34CE1 COM E2/S2:USE STBY XDCR
R Y ELEV MODE XDCR 34CE2 COM E2/S2:USE STBY XDCR

do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-823).

4. Fault Isolation
Subtask 27-93-00-810-082-A

A. If the BITE test gives the maintenance message:
ELAC2 COM OR INPUT OF THS ACTR XDCR1 9CE

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 command position transducer , AMM 27-44-56-000-001 and AMM 27-44-56-400-001.

(2) If the fault continues:

do a check of the wiring of the XDCR COM SPLY signal from the THS actuator (9CE) to the first terminal block, ASM 279313.

(a) If there is no continuity, repair the wiring.
(b) If there is continuity:

do a check and repair the wiring of the XDCR COM V1, V2 signals from the THS actuator (9CE) to the ELAC 2 (2CE2), ASM 279313.

Subtask 27-93-00-700-079-A

B. Do the tests given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:27:57 UTC