Loss of the THS Monitor Transducer-Signal for ELAC2

TASK 27-93-00-810-834-A
Loss of the THS Monitor Transducer-Signal for ELAC2

1. Possible Causes

ACTUATOR-THS [9CE]
electrical load sensing-device
ELAC-2 [2CE2]
monitor position transducer
command position transducer
wiring of the XDCR MON SPLY signal from the THS actuator (9CE) to the first terminal block
wiring of the XDCR MON V1, V2 signals from the THS actuator (9CE) to ELAC2 (2CE2)
wiring of the XDCR COM V1, V2 signals from the THS actuator (9CE) to ELAC2 (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 27-90-00-810-824-A	Loss of the ACS1 Signal of the ELAC2 MON Side and SEC2 MON Side
AMM 27-44-51-000-001	Removal of the Trimmable Horizontal Stabilizer (THS) Actuator
AMM 27-44-51-000-802	Removal of the Electrical Load Sensing Device
AMM 27-44-51-220-004	Detailed Inspection of THSA Upper Attachments for Secondary Load Path Loading
AMM 27-44-51-400-001	Installation of the Trimmable Horizontal Stabilizer (THS) Actuator
AMM 27-44-51-400-802	Installation of the Electrical Load Sensing Device
AMM 27-44-51-710-802	Operational Check of THS Actuator Electrical Load Sensing Device
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 27-93-00-810-284-A ** ON A/C NOT FOR ALL

A. Inspection
(1) Do a detailed inspection of the THSA upper attachments AMM 27-44-51-220-004.
(a) If the inspection is not satisfactory:

Replace the ACTUATOR-THS [9CE] , AMM 27-44-51-000-001 and AMM 27-44-51-400-001.

(b) If the inspection is satisfactory:

Do the operational check of the THS-actuator electrical-load sensing-device AMM 27-44-51-710-802.

1 If the operational check is not satisfactory:

Replace the electrical load sensing-device , AMM 27-44-51-000-802 and AMM 27-44-51-400-802.

2 If the operational check is satisfactory, continue the trouble shooting procedure.

Subtask 27-93-00-700-080-A

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

NOTE: It is necessary to do the ground setting only with ELAC2.

(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 MON OR INPUT OF THS ACTR XDCR1 9CE

Refer to Para. Fault Isolation.

(b) If the ground scanning gives a minimum of 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 condition:
For the maintenance messages of the first list, do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-814).
2 Second condition:
For the maintenance messages of the second list, do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-815).
3 Third condition:
For the 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 a minimum of two maintenance messages from the list below:
ELAC2 MON OR INPUT OF THS ACTR XDCR1 9CE
SEC2 MON OR INPUT OF THS ACTR XDCR3 9CE
L ELEV POS MON XDCR OF ELAC2/SEC2
R Y ELEV POS MON XDCR OF ELAC2/SEC2
L B ELEV MODE XDCR 34CE3
R Y ELEV MODE XDCR 34CE4

Do this trouble shooting procedure (Ref. TSM TASK 27-90-00-810-824).

4. Fault Isolation
Subtask 27-93-00-810-083-A

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

Replace ELAC-2 [2CE2] , AMM 27-93-34-000-001 and AMM 27-93-34-400-001.

(1) If the fault continues:

Replace the monitor position transducer , AMM 27-44-56-000-001 and AMM 27-44-56-400-001.

(2) If the fault continues:

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

(3) If the fault continues:

Do a check of the wiring of the XDCR MON 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 of the wiring of the XDCR MON V1, V2 signals from the THS actuator (9CE) to ELAC2 (2CE2), ASM 279313.
Do a check and repair the wiring of the XDCR COM V1, V2 signals from the THS actuator (9CE) to ELAC2 (2CE2), ASM 279313.

Subtask 27-93-00-700-081-A ** ON A/C NOT FOR ALL

B. Do the tests given in Para. 3.

Subtask 27-93-00-700-081-B ** ON A/C NOT FOR ALL

B. Do the tests given in Para. 3.B.

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