Right Lower Primary Lock Position Failed Locked

TASK 78-31-00-810-978-A
Right Lower Primary Lock Position Failed Locked

1. Possible Causes

R LOWER ACTUATOR [3040KM1]
HARNESS - RIGHT TRAS [4132KS]
HARNESS - PYLON T/R [4130KS]
PROX SENSOR-R T/R LOWER PRIMARY LOCK, CHAN A [4035KS]
PROX SENSOR-R T/R LOWER PRIMARY LOCK, CHAN B [4043KS]
[4000KS]

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	PLIERS - JAWED, SOFT

B. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 71-00-00-810-843-A	Nacelle Component and Harness Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults
AMM 71-13-00-010-802	Opening of the Fan Cowl Doors
AMM 71-13-00-410-802	Closing of the Fan Cowl Doors
AWM 715178
AWM 715179
AMM 73-21-01-000-801	Removal of the Electronic Engine Control (EEC)
AMM 73-21-01-400-801	Installation of the Electronic Engine Control (EEC)
AMM 78-31-00-710-805	Operational Test of Thrust Reverser with MCDU
AMM 78-31-00-710-806	Operational Check of the Thrust Reverser Actuation System (TRAS) Locking Mechanism
AMM 78-31-03-000-801	Removal of the TRAS Locking Actuator
AMM 78-31-03-400-801	Installation of the TRAS Locking Actuator
AMM 78-31-20-000-801	Removal of the TRAS Actuator Proximity-Sensors
AMM 78-31-20-400-801	Installation of the TRAS Actuator Proximity-Sensors
AMM 78-31-61-000-812	Removal of the Right TRAS Monitoring Harness
AMM 78-31-61-000-813	Removal of the Pylon TRAS Monitoring Harness
AMM 78-31-61-400-812	Installation of the Right TRAS Monitoring Harness
AMM 78-31-61-400-813	Installation of the Pylon TRAS Monitoring Harness

3. Fault Confirmation
Subtask 78-31-00-710-293-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.
(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.

4. 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.

CAUTION: MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.

Subtask 78-31-00-810-322-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Get access to right hand lower locking actuator (3040KM1) and EEC (4000KS):
(a) Open the fan cowl doors AMM 71-13-00-010-802.
(2) When thrust reverser cycle is commanded AMM 78-31-00-710-805, on actuator, at proximity sensors (4035KS) and (4043KS), check if target move to unlock position AMM 78-31-00-710-806.
(a) If target does not move, replace R LOWER ACTUATOR [3040KM1] AMM 78-31-03-000-801 and AMM 78-31-03-400-801.
(b) Do the test given in Para. 3.
(3) If you find no damage or if the fault continues:
(a) Check for the correct engagement of connectors (4035KS-A) and (4043KS-A).
1 Repair as necessary.
2 Do the test given in Para. 3.
(4) If the check is OK or if the fault continues, use a PLIERS - JAWED, SOFT to disconnect connectors (40353KS-A) and (4043KS-A) then do a visual inspection of the connector for bent pins, contamination or corrosion or other signs of damage.
(a) If you fin damage, replace HARNESS - RIGHT TRAS [4132KS] AMM 78-31-61-000-812 and AMM 78-31-61-400-812.
(b) Reconnect all connectors.
(c) Do the test given in Para. 3.
(5) If you find no damage, disconnect connectors (4054VC-A) and (4055VC-A) AWM 715178 and AWM 715179.
(a) Do a visual inspection of the connector for bent pins, contamination or corrosion or other signs of damage.
(b) Do a continuity check (less than 5 ohms) between the pins of connectors (4035KS-A) and (4054VC) as follows:

Pin 2 and pin 6
Pin 5 and pin 16
Pin 3 and pin 17.

Pin 2 and pin 6
Pin 5 and pin 16
Pin 3 and pin 17.

(d) Do a check of each wire for wire-to-wire, short circuit and short to ground.
(e) If you find a fault:
1 Replace HARNESS - RIGHT TRAS [4132KS] AMM 78-31-61-000-812 and AMM 78-31-61-400-812.
2 Reconnect all connectors.
3 Do the test given in Para. 3.
(6) If you find no damage, disconnect connectors (491VC-A) and (494VC-A) AWM 715178 and AWM 715179.
(a) Do a visual inspection of the connectors for bent pins, contamination or corrosion or other signs of damage.
(b) Do a continuity check (less than 5 ohms) between the pins of connectors (4054VC-A) and (491VC) as follows:

Pin 6 and pin 13
Pin 16 and pin 29
Pin 17 and pin 30.

Pin 6 and pin 13
Pin 16 and pin 29
Pin 17 and pin 30.

(d) Do a check of each wire for wire-to-wire, short circuit and short to ground.
(e) If you find a fault:
1 Replace HARNESS - PYLON T/R [4130KS] AMM 78-31-61-000-813 and AMM 78-31-61-400-813.
2 Reconnect all connectors.
3 Do the test given in Para. 3.
(7) If you find no damage on wirings or if the fault continues, replace both proximity sensors:
(a) Replace PROX SENSOR-R T/R LOWER PRIMARY LOCK, CHAN A [4035KS] AMM 78-31-20-000-801 and AMM 78-31-20-400-801, and
(b) Replace PROX SENSOR-R T/R LOWER PRIMARY LOCK, CHAN B [4043KS] AMM 78-31-20-000-801 and AMM 78-31-20-400-801.
(c) Do the test given in Para. 3.
(8) If the fault continues:
(a) Replace [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
1 Do the test given in Para. 3.

5. Close-up
Subtask 78-31-00-860-088-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.

[Rev.8 from Aug 2018] 2026.04.04 04:38:17 UTC