DOC AIRBUS | AMM A320FActivation of the Electrical Tertiary Lock System [CFML]
TASK 78-37-00-440-803-A
Activation of the Electrical Tertiary Lock System
MMEL 78-30-04B
THRUST REVERSER DOOR TERTIARY LOCK
A. This procedure gives the instructions to do the activation of the tertiary lock system. This procedure sets the tertiary lock system in the ACTIVE condition.
B. Do this activation procedure when maintenance is complete, before the aircraft is released for flight, and only when specified by another task.
C. When the tertiary lock system is in the ACTIVE condition, the tertiary lock system will lock the translating cowl (transcowl) when the transcowl is in the stowed position. The tertiary lock system only permits the transcowl to deploy if the aircraft is on the ground and the deploy condition is commanded.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 78-37-00-941-054-A
Subtask 78-37-00-440-053-A
Subtask 78-37-00-440-056-A
[Rev.10 from 2021]
2026.04.01 03:37:24 UTC
Activation of the Electrical Tertiary Lock System
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.
1. Reason for the JobMMEL 78-30-04B
THRUST REVERSER DOOR TERTIARY LOCK
A. This procedure gives the instructions to do the activation of the tertiary lock system. This procedure sets the tertiary lock system in the ACTIVE condition.
B. Do this activation procedure when maintenance is complete, before the aircraft is released for flight, and only when specified by another task.
C. When the tertiary lock system is in the ACTIVE condition, the tertiary lock system will lock the translating cowl (transcowl) when the transcowl is in the stowed position. The tertiary lock system only permits the transcowl to deploy if the aircraft is on the ground and the deploy condition is commanded.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | WARNING NOTICE(S) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1) | |
| 437AL, 438AR | |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2) | |
| 447AL, 448AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-13-00-010-803-A | Opening of the Fan Cowl Doors |
| TASK 71-13-00-410-803-A | Closing of the Fan Cowl Doors |
| TASK 78-30-00-040-807-A | Deactivation of the Thrust Reverser System for Nacelle Maintenance (ICU) |
| TASK 78-30-00-440-807-A | Reactivation of the Thrust Reverser System after Nacelle Maintenance (ICU) |
| TASK 78-32-50-010-801-A | Manually Deploy the Translating Cowl |
| TASK 78-32-50-410-801-A | Manually Stow the Translating Cowl |
| TASK 78-36-00-010-806-A | Opening of the Thrust Reverser Cowl Doors |
| TASK 78-36-00-410-806-A | Closing of the Thrust Reverser Cowl Doors |
| TASK 78-37-00-440-802-A | Manual Reset of the Electrical Tertiary Lock System Hook |
Electrical Tertiary Lock SystemSubtask 78-37-00-941-054-A
A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Make sure that the WARNING NOTICE(S) are in position to tell persons not to operate:
(a) Make sure that the WARNING NOTICE(S) is in position to tell persons not to energize FADEC 1(2).
Subtask 78-37-00-010-053-A (1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Make sure that the WARNING NOTICE(S) are in position to tell persons not to operate:
- The ENG/MODE selector switch
- The ENG/MASTER 1(2) control switch.
(a) Make sure that the WARNING NOTICE(S) is in position to tell persons not to energize FADEC 1(2).
B. Get Access
(1) Make sure that the fan cowl doors are open (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
Subtask 78-37-00-040-057-A (1) Make sure that the fan cowl doors are open (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
C. Deactivation of the Thrust Reverser System for Maintenance
Subtask 78-37-00-010-054-A WARNING:
YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.
(1) Make sure that you did the deactivation of the thrust reverser system for nacelle maintenance (Ref. AMM TASK 78-30-00-040-807). D. Make sure that the thrust reverser 6 o'clock aft access door is open (Ref. AMM TASK 78-36-00-010-806).
4. ProcedureSubtask 78-37-00-440-053-A
A. Activation of the Electrical Tertiary Lock System
(1) If the transcowl is in the deployed (aft) position, activate the tertiary lock system (1) as follow:
(a) Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
(b) Turn the lever (2) to the ACTIVE position.
(c) Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
(d) Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
(e) Manually stow the transcowl (Ref. AMM TASK 78-32-50-410-801).
(a) Activate the tertiary lock system as follows (preferred procedure):
1 Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
2 Turn the lever (2) to the ACTIVE position.
3 Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
4 Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
5 Do the manual reset of the tertiary lock system hook (Ref. AMM TASK 78-37-00-440-802).
1 Manually deploy the transcowl (Ref. AMM TASK 78-32-50-010-801).
2 Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
3 Turn the lever (2) to the ACTIVE position.
4 Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
5 Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
6 Manually stow the transcowl (Ref. AMM TASK 78-32-50-410-801).
5. Close-up(1) If the transcowl is in the deployed (aft) position, activate the tertiary lock system (1) as follow:
(a) Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
(b) Turn the lever (2) to the ACTIVE position.
(c) Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
(d) Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
(e) Manually stow the transcowl (Ref. AMM TASK 78-32-50-410-801).
NOTE: The activation task is complete. No more work is necessary.
(2) If the transcowl is in the stowed (forward) position, do one of the two steps that follow: (a) Activate the tertiary lock system as follows (preferred procedure):
1 Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
2 Turn the lever (2) to the ACTIVE position.
3 Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
4 Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
5 Do the manual reset of the tertiary lock system hook (Ref. AMM TASK 78-37-00-440-802).
NOTE: The activation task is complete. No more work is necessary.
(b) Activate the tertiary lock system (1) as follows (alternative procedure): 1 Manually deploy the transcowl (Ref. AMM TASK 78-32-50-010-801).
2 Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
3 Turn the lever (2) to the ACTIVE position.
4 Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
5 Do a check to make sure that the lever (2) aligns with the ACTIVE position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.
6 Manually stow the transcowl (Ref. AMM TASK 78-32-50-410-801).
NOTE: The activation task is complete. No more work is necessary.
Subtask 78-37-00-440-056-A
A. Do the reactivation of the thrust reverser system after maintenance (Ref. AMM TASK 78-30-00-440-807).
Subtask 78-37-00-410-053-A B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser 6 o'clock aft access door (Ref. AMM TASK 78-36-00-410-806).
(3) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(4) Remove the WARNING NOTICE(S).
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser 6 o'clock aft access door (Ref. AMM TASK 78-36-00-410-806).
(3) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
(4) Remove the WARNING NOTICE(S).