Failure of the Nosewheel Steering Feedback Sensor (Control Channel)

TASK 32-51-00-810-811-A
Failure of the Nosewheel Steering Feedback Sensor (Control Channel)

1. Possible Causes

SERVO CTL-N/W STEERING [6GC]
SENSOR-N/W STRG FDBK,CTL CHAN [3GC]
BSCU [10GG]
SENSOR-N/W STRG FDBK,MONITORING CHAN [4GC]
wiring from the BSCU (10GG) to the feedback sensor (3GC)
wiring from the BSCU (10GG) to the N/S steering servo control (6GC)
wiring from the BSCU (10GG) to the feedback sensor (4GC)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 12-14-32-614-004	Check NLG Shock Absorber Charge Pressure
AMM 32-42-34-000-001	Removal of the Braking/Steering Control Unit (BSCU)
AMM 32-42-34-400-001	Installation of the Braking/Steering Control Unit (BSCU)
AMM 32-46-00-740-001	BITE Test of the BSCU
AMM 32-46-00-740-002	BITE Test of the BSCU - Ground Scanning
AMM 32-46-00-740-004	BITE Test of the BSCU - Steering Data
ASM 325101
AMM 32-51-19-000-001	Removal of the Nose Wheel Steering Feedback Sensor P/N C24763000
AMM 32-51-19-400-001	Installation of the Nose Wheel Steering Feedback Sensor P/N C24763000
AMM 32-51-51-000-001	Removal of the Nose-Wheel Steering Servo-Control
AMM 32-51-51-400-001	Installation of the Nose-Wheel Steering Servo-Control
TSM TASK 32-42-00-03	NORMAL BRAKING - TASK SUPPORTING DATA

3. Fault Confirmation
Subtask 32-51-00-740-066-A

A. Test
(1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Do the BSCU GND SCAN AMM 32-46-00-740-002.
(3) Do the BITE test of the BSCU AMM 32-46-00-740-001.
(4) Read the TROUBLE SHOOTING DATA of the BSCU on the MCDU 32-42-00-03 TSM TASK 32-42-00-03 and do the BITE test of the BSCU (steering data) AMM 32-46-00-740-004.

4. Fault Isolation
Subtask 32-51-00-810-060-B ** ON A/C NOT FOR ALL

A. If the tests give the maintenance message STEERING FEEDBACK CONTROL SENSOR 3GC:

Do a check for water (or moisture) in the electrical connector of the N/W steering servo control (6GC).

(1) If there is water:

Examine the electrical connector for corrosion.

(a) If there is corrosion:

Replace the SERVO CTL-N/W STEERING [6GC] AMM 32-51-51-000-001 and AMM 32-51-51-400-001.

(b) If there is no corrosion:

Dry the electrical connector of the N/W steering servo control
Make sure that the heat-shrink sleeve of the electrical connector is in good condition
Connect the electrical connector to the N/W steering servo control (6GC) and fold back the end of the heat-shrink sleeve on the connector to cover it fully.

(2) If there is no water:

Replace the SENSOR-N/W STRG FDBK,CTL CHAN [3GC] AMM 32-51-19-000-001 and AMM 32-51-19-400-001.

(3) If the fault continues:

Replace the BSCU [10GG] AMM 32-42-34-000-001 and AMM 32-42-34-400-001.

(4) If the fault continues:

Replace the SENSOR-N/W STRG FDBK,MONITORING CHAN [4GC] AMM 32-51-19-000-001 and AMM 32-51-19-400-001.

(5) If the fault continues:

Do a check and repair the wiring from the BSCU (10GG) to the feedback sensor (3GC) pins AB/15E, 15F, 8E, 8F, 9E, 9F to pins A/A, B, C, D, E, F ASM 325101.

(6) If the fault continues:

Do a check and repair the wiring from the BSCU (10GG) to the N/S steering servo control (6GC) pins AB/12E, 12F, 13E, 13F, 14E, 14F to pins A/G, H, E, F, C, D ASM 325101.

(7) If the fault continues:

Do a check and repair the wiring from the BSCU (10GG) to the feedback sensor (4GC) pins AB/14E, 14F, 10E, 10F, 11F, 11E to pins A/A, B, C, D, E, F ASM 325101.

(8) If the fault continues:
(a) Replace the SERVO CTL-N/W STEERING [6GC] AMM 32-51-51-000-001 and AMM 32-51-51-400-001.
(9) If the fault continues:

Do the check of the charge pressure of the nose landing gear shock absorber AMM 12-14-32-614-004

Subtask 32-51-00-810-060-C ** ON A/C NOT FOR ALL

A. If the tests give the maintenance message STEERING FEEDBACK CONTROL SENSOR (3GC):

Do a check for water (or moisture) in the electrical connector of the N/W steering servo control (6GC).