DOC AIRBUS | TSM A320FRight Tertiary Lock Position Failed Locked
TASK 78-31-00-810-991-A
Right Tertiary Lock Position Failed Locked
1. Possible Causes
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 78-31-00-710-308-A ** ON A/C NOT FOR ALL
Subtask 78-31-00-860-099-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:38:19 UTC
Right Tertiary Lock Position Failed Locked
1. Possible Causes
tubes/hoses - aircraft wiring
- relay 2EG1
- relay 3EG1
- relay 2EG2
- relay 3EG2
- TRAS TRACK LOCK WIRE HARNESS [4137KS]
- harness parts
- RH TRAS LOCK VALVE [4142KS]
- TRAS TRACK LOCK WIRE HARNESS [4135KS]
- TERTIARY LOCK UNIT-TRAS, R [3022KM]
[4000KS]
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | MULTIMETER - STANDARD |
| No specific | 1 | PLIERS - JAWED, SOFT |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 71-00-00-810-843-A | Nacelle Component and Harness Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults |
| AMM 70-70-00-910-803 | SPOP 6 - Cleaning of the Contact Points and Wiring Harnesses |
| AMM 71-13-00-010-802 | Opening of the Fan Cowl Doors |
| AMM 71-13-00-410-802 | Closing of the Fan Cowl Doors |
| AMM 73-21-01-000-801 | Removal of the Electronic Engine Control (EEC) |
| AMM 78-31-00-200-801 | General Visual Inspection (GVI) of the Thrust Reverser Actuation System (TRAS) |
| AMM 78-31-00-710-805 | Operational Test of Thrust Reverser with MCDU |
| AMM 78-31-50-000-801 | Removal of the TRAS Hydraulic Tubes and Hoses |
| AMM 78-31-50-400-801 | Installation of the TRAS Hydraulic Tubes and Hoses |
| AMM 78-31-62-000-802 | Removal of the Right TRAS Track Lock Harness |
| AMM 78-31-62-000-803 | Removal of the Pylon TRAS Track Lock Harness |
| AMM 78-31-62-400-802 | Installation of the Right TRAS Track Lock Harness |
| AMM 78-31-62-400-803 | Installation of the Pylon TRAS Track Lock Harness |
| AWM 783601 | |
| AWM 783602 | |
| AWM 783603 | |
| AMM 78-37-00-040-801 | Deactivation of the TRAS Track Lock |
| AMM 78-37-01-000-801 | Removal of the Thrust Reverser Actuator System (TRAS) Track Lock |
| AMM 78-37-01-400-801 | Installation of the Thrust Reverser Actuator System (TRAS) Track Lock |
| AMM 78-37-02-000-801 | Removal of the TRAS Track Lock Valve |
| AMM 78-37-02-400-801 | Installation of the TRAS Track Lock Valve |
Subtask 78-31-00-710-308-A ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser with the MCDU to confirm this fault AMM 78-31-00-710-805.
(a) Monitor the engine for reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault IsolationNOTE: Before to do the test, make sure that the circuit breaker 1EG1(2) is closed. Refer to the Para. 4.B.
(1) If the maintenance message does not come back, troubleshoot as described in the nacelle component and harness troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-843). (a) Monitor the engine for reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.
WARNING:
OPEN THE APPLICABLE CIRCUIT BREAKER(S) TO ELECTRICALLY ISOLATE THE SYSTEM BEFORE INSPECTION/CHECK OF THE HARNESSES.
IF YOU DO NOT OBEY THIS INSTRUCTION, THERE CAN BE 115VAC IN THE HARNESSES. THIS CAN CAUSE DAMAGE TO EQUIPMENT AND INJURY TO MAINTENANCE PERSONNEL.
Subtask 78-31-00-810-335-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Check if same fault message comes on for left track lock also.
(2) Open the fan cowl doors AMM 71-13-00-010-802.
(3) If fault message comes on both sides:
(a) Check for hydraulic leakage between pylon and T piece.
1 Inspect hydraulic tubes and hoses.
a Replacetubes/hoses as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
2 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(b) If no leakage found or if the fault continues, check for hydraulic leakage in pylon.
1 Get access to HCU:
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
2 Inspect hydraulic tubes and hoses.
a Replacetubes/hoses as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
3 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(c) If no leakage found or fault continues on ENG 1:
1 Open the circuit breaker, refer to the Para. 4.B.
2 Remove relays (2EG1) and (3EG1).
3 Check all wires on VU for continuity (less than 5 ohms resistance), wire-to-wire short and short to ground AWM 783601.
4 Check wire between pin 34 on terminal block (2240VC) and pin Y on terminal block 83 VU.
5 If wiring is not OK:
a Repair aircraft wiring .
6 If wiring is OK:
a Replace relay 2EG1 and relay 3EG1 .
(d) If no leakage found or fault continues on ENG 2:
1 Open the circuit breaker, refer to the Para. 4.B.
2 Remove relays (2EG2) and (3EG2).
3 Check all wires on VU for continuity (less than 5 ohms resistance), wire-to-wire short and short to ground AWM 783602.
4 If wiring is not OK:
a Repair aircraft wiring .
5 If wiring is OK:
a Replace relay 2EG2 and relay 3EG2 .
(e) Do the test given in Para. 3.
(4) If fault message comes only on right sides:
(a) Check for hydraulic leakage between T piece and right track lock.
1 Inspect hydraulic tubes and hoses AMM 78-31-00-200-801.
a Replacetubes/hoses as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
2 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(b) Open the circuit breaker, refer to the Para. 4.B.
(c) If the fault continues:
1 Inspect the harness (4137KS) and connector (4142KS-A) at right tertiary lock valve and connector (4051VC-A) on right thrust reverser cowl-door for:
a Inspect for harness damage.
b Inspect for loose or damaged connectors.
1 Replace TRAS TRACK LOCK WIRE HARNESS [4137KS] AMM 78-31-62-000-802 and AMM 78-31-62-400-802.
(e) Do the test given in Para. 3.
(f) Open the circuit breaker, refer to the Para. 4.B.
(g) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector (4142KS-A) at right track lock valve and connector (4051VC-A) on right thrust reverser cowl-door.
(h) Examine all harness connectors and also connector (4142KS) at valve side:
1 Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face:
a Replace harness parts or RH TRAS LOCK VALVE [4142KS] as necessary AMM 78-37-02-000-801 and AMM 78-37-02-400-801.
2 Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
3 Reconnect the electrical connectors.
4 Do the test given in Para. 3.
(i) Open the circuit breaker, refer to the Para. 4.B.
(j) If the fault continues:
1 Inspect the harness (4135KS) and connector (752VC-A) at pylon junction box for:
2 Inspect for harness damage.
3 Inspect for loose or damaged connectors.
1 Replace TRAS TRACK LOCK WIRE HARNESS [4135KS] AMM 78-31-62-000-803 and AMM 78-31-62-400-803.
(l) Do the test given in Para. 3.
(m) Open the circuit breaker, refer to the Para. 4.B.
(n) If no problems are found with the harness or the fault continues, disconnect the electrical connector (752VC-A) at pylon junction box for:
1 Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
2 Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
3 Reconnect the electrical connectors.
4 Do the test given in Para. 3.
(o) Open the circuit breaker, refer to the Para. 4.B.
(p) If no problems are found with the harness or the fault continues, disconnect the electrical connector (4142KS-A) from the right track Lock valve connector (4051VC-A) from right thrust reverser cowl-door and connector (752VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the circuits in the harness. Refer to Table 1. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
Table 1: Track Lock Valve Connector Contacts
4 Check for ground at pin 4 of connector (4142KS-A).
(q) If a problem is found with the harness or connectors:
1 Replace TRAS TRACK LOCK WIRE HARNESS [4137KS] AMM 78-31-62-000-802 and AMM 78-31-62-400-802, and/or
2 Replace TRAS TRACK LOCK WIRE HARNESS [4135KS] AMM 78-31-62-000-803 and AMM 78-31-62-400-803.
3 Do the test given in Para. 3.
(r) Open the circuit breaker, refer to the Para. 4.B.
(s) If no problems are found with the harness or the fault continues, check that torque value to move right track lock in unlocked position is no more than 177 lbf.in (2.00 m.daN) and check that movement is smooth AMM 78-37-00-040-801.
1 If check is not OK:
a Replace TERTIARY LOCK UNIT-TRAS, R [3022KM] AMM 78-37-01-000-801 and AMM 78-37-01-400-801.
b Do the test given in Para. 3.
(t) If check is OK or the fault continues, check the aircraft wiring:
1 Open the circuit breaker, refer to the Para. 4.B.
2 For fault on ENG 1 AWM 783601 and AWM 783603:
a Remove 120VU panel, disconnect the electrical connector (2214VC-A) from the 120VU panel, connector (421VC-A) and connector (752VC1-A).
b Inspect and clean connectors.
c Refer to Table 2. Look for:
Table 2: Track Lock Valve Connector Contacts
d Check for ground at pin 29 of connector (421VC).
e Repair wiring as necessary.
f Connect connectors and install 120VU panel.
3 For fault on ENG 2 AWM 783602 and AWM 783603.
a Remove 120VU panel, disconnect the electrical connector (2246VC-A) from the 120VU panel, connector (420VC-A) and connector (752VC2).
b Inspect and clean connectors.
c Refer to Table 3. Look for:
Table 3: Track Lock Valve Connector Contacts
d Check for ground at pin 29 of connector (420VC).
e Repair wiring as necessary.
f Connect connectors and install 120VU panel.
4 Do the test given in Para. 3.
(u) If the fault continues:
1 Replace RH TRAS LOCK VALVE [4142KS] AMM 78-37-02-000-801 and AMM 78-37-02-400-801.
2 Do the test given in Para. 3.
(v) If the fault continues:
1 Replace
2 Do the test given in Para. 3.
Subtask 78-31-00-865-056-A ** ON A/C NOT FOR ALL (1) Check if same fault message comes on for left track lock also.
(2) Open the fan cowl doors AMM 71-13-00-010-802.
(3) If fault message comes on both sides:
(a) Check for hydraulic leakage between pylon and T piece.
1 Inspect hydraulic tubes and hoses.
a Replace
2 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(b) If no leakage found or if the fault continues, check for hydraulic leakage in pylon.
1 Get access to HCU:
- Remove the access panel on the pylon to get access to the HCU:
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
2 Inspect hydraulic tubes and hoses.
a Replace
3 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(c) If no leakage found or fault continues on ENG 1:
1 Open the circuit breaker, refer to the Para. 4.B.
2 Remove relays (2EG1) and (3EG1).
3 Check all wires on VU for continuity (less than 5 ohms resistance), wire-to-wire short and short to ground AWM 783601.
4 Check wire between pin 34 on terminal block (2240VC) and pin Y on terminal block 83 VU.
5 If wiring is not OK:
a Repair aircraft wiring .
6 If wiring is OK:
a Replace relay 2EG1 and relay 3EG1 .
(d) If no leakage found or fault continues on ENG 2:
1 Open the circuit breaker, refer to the Para. 4.B.
2 Remove relays (2EG2) and (3EG2).
3 Check all wires on VU for continuity (less than 5 ohms resistance), wire-to-wire short and short to ground AWM 783602.
4 If wiring is not OK:
a Repair aircraft wiring .
5 If wiring is OK:
a Replace relay 2EG2 and relay 3EG2 .
(e) Do the test given in Para. 3.
(4) If fault message comes only on right sides:
(a) Check for hydraulic leakage between T piece and right track lock.
1 Inspect hydraulic tubes and hoses AMM 78-31-00-200-801.
a Replace
2 If hydraulic leakage corrected:
a Do the test given in Para. 3.
(b) Open the circuit breaker, refer to the Para. 4.B.
(c) If the fault continues:
1 Inspect the harness (4137KS) and connector (4142KS-A) at right tertiary lock valve and connector (4051VC-A) on right thrust reverser cowl-door for:
a Inspect for harness damage.
b Inspect for loose or damaged connectors.
NOTE: Loose connectors must be disconnected and examined for further wear or damage.
(d) If a problem is found with the harness or connectors: 1 Replace TRAS TRACK LOCK WIRE HARNESS [4137KS] AMM 78-31-62-000-802 and AMM 78-31-62-400-802.
(e) Do the test given in Para. 3.
(f) Open the circuit breaker, refer to the Para. 4.B.
(g) If no problems are found with the harness or the fault continues, use a PLIERS - JAWED, SOFT to disconnect the electrical connector (4142KS-A) at right track lock valve and connector (4051VC-A) on right thrust reverser cowl-door.
(h) Examine all harness connectors and also connector (4142KS) at valve side:
1 Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face:
a Replace harness parts or RH TRAS LOCK VALVE [4142KS] as necessary AMM 78-37-02-000-801 and AMM 78-37-02-400-801.
2 Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
3 Reconnect the electrical connectors.
4 Do the test given in Para. 3.
(i) Open the circuit breaker, refer to the Para. 4.B.
(j) If the fault continues:
1 Inspect the harness (4135KS) and connector (752VC-A) at pylon junction box for:
2 Inspect for harness damage.
3 Inspect for loose or damaged connectors.
NOTE: Loose connectors must be disconnected and examined for further wear or damage.
(k) If a problem is found with the harness or connectors: 1 Replace TRAS TRACK LOCK WIRE HARNESS [4135KS] AMM 78-31-62-000-803 and AMM 78-31-62-400-803.
(l) Do the test given in Para. 3.
(m) Open the circuit breaker, refer to the Para. 4.B.
(n) If no problems are found with the harness or the fault continues, disconnect the electrical connector (752VC-A) at pylon junction box for:
1 Examine the pins and sockets (contacts) for alignment and damage. Look for contacts pushed rearward into the connector face. Replace parts as necessary.
2 Clean the contacts with contact cleaner and clean cloth per SPOP 6. Blow dry with air (at less than 30 psi) across connector face AMM 70-70-00-910-803.
3 Reconnect the electrical connectors.
4 Do the test given in Para. 3.
(o) Open the circuit breaker, refer to the Para. 4.B.
(p) If no problems are found with the harness or the fault continues, disconnect the electrical connector (4142KS-A) from the right track Lock valve connector (4051VC-A) from right thrust reverser cowl-door and connector (752VC-A) from the pylon junction box. Use a MULTIMETER - STANDARD to test the circuits in the harness. Refer to Table 1. Look for:
1 Wire-to-wire shorts
2 Shorts to ground
3 Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.
Table 1: Track Lock Valve Connector Contacts
| (4142KS-A) Connector Pins | (4151KS-A) Connector Pins | (752VC-A) Connector Pin |
|---|---|---|
| 2 | 2 | 4 |
| 3 | 3 | 5 |
(q) If a problem is found with the harness or connectors:
1 Replace TRAS TRACK LOCK WIRE HARNESS [4137KS] AMM 78-31-62-000-802 and AMM 78-31-62-400-802, and/or
2 Replace TRAS TRACK LOCK WIRE HARNESS [4135KS] AMM 78-31-62-000-803 and AMM 78-31-62-400-803.
3 Do the test given in Para. 3.
(r) Open the circuit breaker, refer to the Para. 4.B.
(s) If no problems are found with the harness or the fault continues, check that torque value to move right track lock in unlocked position is no more than 177 lbf.in (2.00 m.daN) and check that movement is smooth AMM 78-37-00-040-801.
1 If check is not OK:
a Replace TERTIARY LOCK UNIT-TRAS, R [3022KM] AMM 78-37-01-000-801 and AMM 78-37-01-400-801.
b Do the test given in Para. 3.
(t) If check is OK or the fault continues, check the aircraft wiring:
1 Open the circuit breaker, refer to the Para. 4.B.
2 For fault on ENG 1 AWM 783601 and AWM 783603:
a Remove 120VU panel, disconnect the electrical connector (2214VC-A) from the 120VU panel, connector (421VC-A) and connector (752VC1-A).
b Inspect and clean connectors.
c Refer to Table 2. Look for:
- Wire-to-wire shorts
- Shorts to ground
- Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.
Table 2: Track Lock Valve Connector Contacts
| 2214VC-A Connector Pins | 421VC/421VC-A Connector Pins | 752VC1 Connector Pin |
|---|---|---|
| 17 | 28 | 4 |
| 29 | 5 |
e Repair wiring as necessary.
f Connect connectors and install 120VU panel.
3 For fault on ENG 2 AWM 783602 and AWM 783603.
a Remove 120VU panel, disconnect the electrical connector (2246VC-A) from the 120VU panel, connector (420VC-A) and connector (752VC2).
b Inspect and clean connectors.
c Refer to Table 3. Look for:
- Wire-to-wire shorts
- Shorts to ground
- Continuity (less than 5 ohms resistance).
NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.
Table 3: Track Lock Valve Connector Contacts
| 2246VC-A Connector Pins | 420VC/420VC-A Connector Pins | 752VC2 Connector Pin |
|---|---|---|
| 21 | 28 | 4 |
| 29 | 5 |
e Repair wiring as necessary.
f Connect connectors and install 120VU panel.
4 Do the test given in Para. 3.
(u) If the fault continues:
1 Replace RH TRAS LOCK VALVE [4142KS] AMM 78-37-02-000-801 and AMM 78-37-02-400-801.
2 Do the test given in Para. 3.
(v) If the fault continues:
1 Replace
2 Do the test given in Para. 3.
B. Open, safety and tag this(these) circuit breaker(s):
5. Close-up| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1) | |||
| 121VU | ENG1/REV/LOCK | 1EG1 | N44 |
| FOR FIN: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2) | |||
| 121VU | ENG2/REV/LOCK | 1EG2 | N45 |
Subtask 78-31-00-860-099-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.
(b) If necessary, close the pylon access panel:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.
(b) If necessary, close the pylon access panel:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)