DOC AIRBUS | TSM A320FElectrical failure of the Alternate Brake Servovalve
TASK 32-43-00-810-804-A
Electrical failure of the Alternate Brake Servovalve
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 32-43-00-740-056-A ** ON A/C NOT FOR ALL
Subtask 32-43-00-810-053-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:31:40 UTC
Electrical failure of the Alternate Brake Servovalve
1. Possible Causes
- SERVOVALVE-ALTN BRK WHEEL 4 [42GG]
- BSCU [10GG]
wiring from the BSCU (10GG) to the alternate brake servovalve (42GG)
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 31-32-00-869-002 | Procedure for the Class 3 Fault Reading |
| 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) |
| ASM 324301 | |
| AMM 32-43-27-000-001 | Removal of the Alternate Brake Servovalve |
| AMM 32-43-27-400-001 | Installation of the Alternate Brake Servovalve |
| AMM 32-46-00-740-001 | BITE Test of the BSCU |
Subtask 32-43-00-740-056-A ** ON A/C NOT FOR ALL
A. Test
(1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Read the CLASS 3 FAULTS report AMM 31-32-00-869-002.
Subtask 32-43-00-740-056-C ** ON A/C NOT FOR ALL (1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Read the CLASS 3 FAULTS report AMM 31-32-00-869-002.
A. Test
(1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Do the BITE test of the BSCU AMM 32-46-00-740-001.
4. Fault Isolation(1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Do the BITE test of the BSCU AMM 32-46-00-740-001.
Subtask 32-43-00-810-053-A ** ON A/C NOT FOR ALL
A. If the CLASS 3 FAULTS report gives the maintenance message BRK ALTN SERVOVALVE 42GG:
Subtask 32-43-00-810-053-B ** ON A/C NOT FOR ALL - Do a continuity/resistance test at the servovalve.
NOTE: The resistance must be between:
(1) If the test is not OK: - 90 and 100 ohms for P/N C20XXXXXX between the terminals A and C, (E and F) for coil B1, (B2).
- 45 and 50 ohms for P/N E21XXXXXX between the terminals A and C, (A and F) for coil B1, (B2).
- Replace the SERVOVALVE-ALTN BRK WHEEL 4 [42GG] , AMM 32-43-27-000-001 and AMM 32-43-27-400-001.
- Replace the BSCU [10GG] , AMM 32-42-34-000-001 and AMM 32-42-34-400-001.
- Do a check and repair the
wiring from the BSCU (10GG) to the alternate brake servovalve (42GG) pins AB/4A, 4B to pins A/C, A ASM 324301.
A. If the test gives the maintenance message BRK ALTN SERVOVLV(42GG):
Subtask 32-43-00-740-057-A ** ON A/C NOT FOR ALL - Do a continuity/resistance test at the servovalve.
NOTE: The resistance must be between:
(1) If the test is not OK: - 90 and 100 ohms for P/N C20XXXXXX between the terminals A and C, (E and F) for coil B1, (B2).
- 45 and 50 ohms for P/N E21XXXXXX between the terminals A and C, (A and F) for coil B1, (B2).
- Replace the SERVOVALVE-ALTN BRK WHEEL 4 [42GG] , AMM 32-43-27-000-001 and AMM 32-43-27-400-001.
- Replace the BSCU [10GG] , AMM 32-42-34-000-001 and AMM 32-42-34-400-001.
- Do a check and repair the
wiring from the BSCU (10GG) to the alternate brake servovalve (42GG) pins AB/4A, 4B to pins A/C, A ASM 324301.
B. Do the test given in Para. 3.A.