DOC AIRBUS | AMM A320FInstallation of the Direction Control Unit (DCU) [CFML]
TASK 78-31-52-400-802-A
Installation of the Direction Control Unit (DCU)
A. This task gives the instructions to install the Direction Control Unit (DCU) on the thrust reverser.
B. The upper actuator is also known as the synchronized locking feedback actuator.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Expendable Parts
E. Referenced Information
3. Job Set-up
Subtask 78-31-52-941-054-A
Subtask 78-31-52-410-054-A
[Rev.10 from 2021]
2026.04.01 03:35:33 UTC
Installation of the Direction Control Unit (DCU)
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.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
1. Reason for the JobA. This task gives the instructions to install the Direction Control Unit (DCU) on the thrust reverser.
B. The upper actuator is also known as the synchronized locking feedback actuator.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.CPNCL00062) | Synthetic base lubricating oil - turbine engine |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1) | |
| 437AL, 438AR, 451AL | |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2) | |
| 447AL, 448AR, 461AL | |
| FIG.ITEM | DESIGNATION | IPC-CSN |
|---|---|---|
| 19 | WASHER | AIPC 78-31-49-05-020 |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-70-00-910-804-A | Electrical Standard Practices |
| 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 71-51-43-400-806-A | Installation of the Thrust Reverser Actuation System Electrical Harnesses |
| TASK 73-29-00-740-804-A | Thrust Reverser Cycling Test (Menu Mode) |
| 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 78-31-41-820-801-A | Synchronize the Thrust Reverser Actuators |
| TASK 78-31-44-400-802-A | Installation of the Sync Tubes, Sync Shafts, Flex Tube and Flex Shaft |
| 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 |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1) | |
| TASK 29-10-00-863-001-A | Pressurize the Green Hydraulic System with a Hydraulic Ground Power-Cart |
| TASK 29-10-00-864-001-A | Depressurize the Green Hydraulic System |
| TASK 29-14-00-614-001-A | Depressurization of the Hydraulic Reservoirs |
| TASK 29-14-00-614-002-A | Pressurization of the Hydraulic Reservoirs through the Ground Connector |
| TASK 29-14-00-614-002-A-01 | Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU) |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2) | |
| TASK 29-10-00-863-002-A | Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart |
| TASK 29-10-00-864-002-A | Depressurize the Yellow Hydraulic System |
| TASK 29-14-00-614-001-A | Depressurization of the Hydraulic Reservoirs |
| TASK 29-14-00-614-002-A | Pressurization of the Hydraulic Reservoirs through the Ground Connector |
| TASK 29-14-00-614-002-A-01 | Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU) |
Direction Control Unit (DCU)Subtask 78-31-52-941-054-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 ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Make sure that the WARNING NOTICE(S) is in position to tell persons not to energize FADEC 1(2).
Subtask 78-31-52-010-057-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 ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) 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
(2) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position below the left fan-cowl door.
Subtask 78-31-52-864-053-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
(2) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position below the left fan-cowl door.
C. Depressurization of the Aircraft Hydraulic Systems
(1) Make sure that the WARNING NOTICE(S) is in position to tell persons not to pressurize the applicable system.
(a) On the HYD/FUEL panel 40VU of the overhead panel
(b) On the ground service panel of the applicable hydraulic system.
(2) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
(a) Make sure that the Green hydraulic system is depressurized (Ref. AMM TASK 29-10-00-864-001).
(b) Make sure that the reservoir of the Green hydraulic system is depressurized (Ref. AMM TASK 29-14-00-614-001).
(3) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
(a) Make sure that the Yellow hydraulic system is depressurized (Ref. AMM TASK 29-10-00-864-002).
(b) Make sure that the reservoir of the Yellow hydraulic system is depressurized (Ref. AMM TASK 29-14-00-614-001).
Subtask 78-31-52-040-053-A (1) Make sure that the WARNING NOTICE(S) is in position to tell persons not to pressurize the applicable system.
(a) On the HYD/FUEL panel 40VU of the overhead panel
(b) On the ground service panel of the applicable hydraulic system.
(2) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
(a) Make sure that the Green hydraulic system is depressurized (Ref. AMM TASK 29-10-00-864-001).
(b) Make sure that the reservoir of the Green hydraulic system is depressurized (Ref. AMM TASK 29-14-00-614-001).
(3) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
(a) Make sure that the Yellow hydraulic system is depressurized (Ref. AMM TASK 29-10-00-864-002).
(b) Make sure that the reservoir of the Yellow hydraulic system is depressurized (Ref. AMM TASK 29-14-00-614-001).
D. Deactivation of the Thrust Reverser System for Maintenance
Subtask 78-31-52-010-059-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). E. Get Access
(1) Make sure that the left thrust-reverser cowl-door is open (Ref. AMM TASK 78-36-00-010-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL
4. Procedure(1) Make sure that the left thrust-reverser cowl-door is open (Ref. AMM TASK 78-36-00-010-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL
WARNING:
DO NOT GET HYDRAULIC FLUID ON YOUR SKIN, IN YOUR EYES OR IN YOUR MOUTH. HYDRAULIC FLUID IS POISONOUS AND CAN GO THROUGH YOUR SKIN AND INTO YOUR BODY. FLUSH HYDRAULIC FLUID FROM YOUR EYES, MOUTH OR SKIN WITH WATER. GET MEDICAL AID IF YOU GET HYDRAULIC FLUID IN YOUR EYES OR MOUTH.
WARNING:
OBEY THE HYDRAULIC SAFETY PROCEDURES.
WARNING:
DO NOT TOUCH THE HYDRAULIC SYSTEM COMPONENTS FOR A SHORT TIME AFTER THE ENGINE IS SHUTDOWN. THE ENGINE COMPONENTS STAY HOT FOR SOME TIME AND CAN CAUSE INJURY.
CAUTION:
DO NOT LET HYDRAULIC FLUID FALL ON THE ENGINE. UNWANTED HYDRAULIC FLUID MUST BE REMOVED IMMEDIATELY WITH A CLEAN LINT FREE CLOTH. THE FLUID CAN CAUSE DAMAGE TO THE SURFACE PROTECTION AND TO SOME PARTS.
Subtask 78-31-52-420-051-A A. Installation of the Direction Control Unit (DCU)
(1) Remove COVER - PROTECTION and CAP - PROTECTION from all the openings, tubes, hoses and connectors.
(2) Lubricate the threads of the four bolts (14) with Synthetic base lubricating oil - turbine engine (Material No.CPNCL00062) .
(3) Install the DCU (2) as follows:
(a) Install the two washers (16) and the two bolts (14) that attach the DCU (2) to the forward frame (8).
(b) Install the two bolts (14) that attach the DCU (2) and the bracket (15) to the forward frame (8).
(c) Tighten the four bolts (14) hand-tight to keep the DCU (2) attached to the forward frame (8) for the installation of the attached parts.
(4) Install the hydraulic tube (10) as follows:
(a) Put the hydraulic tube (10) in position on the DCU (2) and connect the coupling nut to the DCU (2) and the tee-connector (3) hand-tight.
(b) TRIPLE TORQUE the coupling nut on hydraulic tube (10) at the DCU (2) to between 8.42 and 7.01 m.daN (62.09 and 51.70 lbf.ft )
.
(c) TORQUE the coupling nut at the tee-connector (3) to between 8.42 and 7.01 m.daN (62.09 and 51.70 lbf.ft ).
(5) Install the hydraulic tube (12) on the bracket (7) and the DCU (2) as follows:
(a) Loosely attach the hydraulic tube (12) to the bracket (7) with the two new AIPC 78-31-49-05-020 WASHER (19) and the two nuts (17).
(b) Connect the coupling nuts of the hydraulic tube (12) to the DCU (2) and the upper actuator (9) hand-tight.
(c) TORQUE the two nuts (17) to between 3.48 and 2.96 m.daN (25.66 and 21.83 lbf.ft ).
(d) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (12) to the DCU (2) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft ).
(6) Install the hydraulic tube (11) on the bracket (7) as follows:
(a) Loosely attach the hydraulic tube (11) to the bracket (7) with the two new AIPC 78-31-49-05-020 WASHER (19) and the two nuts (17).
(b) Connect the coupling nuts of the hydraulic tube (11) to the DCU (2) and the upper actuator (9) hand-tight.
(c) TRIPLE TORQUE the two nuts (17) to between 3.48 and 2.96 m.daN (25.66 and 21.83 lbf.ft ).
(7) Install the hydraulic tube (11) as follows:
(a) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (11) to the DCU (2) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft ).
(b) TORQUE the coupling nut that connects the hydraulic tube (11) to the upper actuator (9) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft ).
(c) Connect the pylon hose (21) to the hydraulic tube (11) hand-tight.
(d) TRIPLE TORQUE the coupling nut of the pylon hose (21) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft ).
(8) Install the hydraulic tube (12) as follows:
(a) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (12) to the upper actuator (9) to between 3.16 and 2.43 m.daN (23.30 and 17.92 lbf.ft ).
(b) Connect the coupling nut of the pylon hose (20) to the hydraulic tube (12) hand-tight.
(c) TRIPLE TORQUE the coupling nut of the pylon hose (20) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft ).
(9) TRIPLE TORQUE the four bolts (14) that attach the DCU (2) to between 0.98 and 0.72 m.daN (86.73 and 63.72 lbf.in ).
(10) Connect the electrical connectors (4) and (5) to the DCU (2) (Ref. AMM TASK 70-70-00-910-804).
5. Close-up(1) Remove COVER - PROTECTION and CAP - PROTECTION from all the openings, tubes, hoses and connectors.
(2) Lubricate the threads of the four bolts (14) with Synthetic base lubricating oil - turbine engine (Material No.CPNCL00062) .
(3) Install the DCU (2) as follows:
(a) Install the two washers (16) and the two bolts (14) that attach the DCU (2) to the forward frame (8).
(b) Install the two bolts (14) that attach the DCU (2) and the bracket (15) to the forward frame (8).
(c) Tighten the four bolts (14) hand-tight to keep the DCU (2) attached to the forward frame (8) for the installation of the attached parts.
(4) Install the hydraulic tube (10) as follows:
(a) Put the hydraulic tube (10) in position on the DCU (2) and connect the coupling nut to the DCU (2) and the tee-connector (3) hand-tight.
(b) TRIPLE TORQUE the coupling nut on hydraulic tube (10) at the DCU (2) to between 8.42 and 7.01 m.daN (62.09 and 51.70 lbf.ft )
. (c) TORQUE the coupling nut at the tee-connector (3) to between 8.42 and 7.01 m.daN (62.09 and 51.70 lbf.ft )
. (5) Install the hydraulic tube (12) on the bracket (7) and the DCU (2) as follows:
(a) Loosely attach the hydraulic tube (12) to the bracket (7) with the two new AIPC 78-31-49-05-020 WASHER (19) and the two nuts (17).
(b) Connect the coupling nuts of the hydraulic tube (12) to the DCU (2) and the upper actuator (9) hand-tight.
(c) TORQUE the two nuts (17) to between 3.48 and 2.96 m.daN (25.66 and 21.83 lbf.ft )
. (d) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (12) to the DCU (2) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft )
. (6) Install the hydraulic tube (11) on the bracket (7) as follows:
(a) Loosely attach the hydraulic tube (11) to the bracket (7) with the two new AIPC 78-31-49-05-020 WASHER (19) and the two nuts (17).
(b) Connect the coupling nuts of the hydraulic tube (11) to the DCU (2) and the upper actuator (9) hand-tight.
(c) TRIPLE TORQUE the two nuts (17) to between 3.48 and 2.96 m.daN (25.66 and 21.83 lbf.ft )
. (7) Install the hydraulic tube (11) as follows:
(a) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (11) to the DCU (2) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft )
. (b) TORQUE the coupling nut that connects the hydraulic tube (11) to the upper actuator (9) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft )
. (c) Connect the pylon hose (21) to the hydraulic tube (11) hand-tight.
(d) TRIPLE TORQUE the coupling nut of the pylon hose (21) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft )
. (8) Install the hydraulic tube (12) as follows:
(a) TRIPLE TORQUE the coupling nut that connects the hydraulic tube (12) to the upper actuator (9) to between 3.16 and 2.43 m.daN (23.30 and 17.92 lbf.ft )
. (b) Connect the coupling nut of the pylon hose (20) to the hydraulic tube (12) hand-tight.
(c) TRIPLE TORQUE the coupling nut of the pylon hose (20) to between 6.21 and 5.31 m.daN (45.80 and 39.16 lbf.ft )
. (9) TRIPLE TORQUE the four bolts (14) that attach the DCU (2) to between 0.98 and 0.72 m.daN (86.73 and 63.72 lbf.in )
. (10) Connect the electrical connectors (4) and (5) to the DCU (2) (Ref. AMM TASK 70-70-00-910-804).
NOTE: If necessary, use PLIERS - JAWED, SOFT.
(11) Tighten the over-the-top flex tube (6) (Ref. AMM TASK 78-31-44-400-802). NOTE: It is not necessary to do the synchronization (Ref. AMM TASK 78-31-41-820-801) as a part of this procedure because it will be done in Step 5.B.(1) below.
(12) Install the tertiary lock system harnesses (1) to the DCU (2) and the upper actuator (9) (Ref. AMM TASK 71-51-43-400-806). Subtask 78-31-52-410-054-A
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the left thrust-reverser cowl-door (Ref. AMM TASK 78-36-00-410-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL
Subtask 78-31-52-860-053-A (1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the left thrust-reverser cowl-door (Ref. AMM TASK 78-36-00-410-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL
B. Put the aircraft back to its initial configuration.
(1) Synchronize the thrust reverser actuators (Ref. AMM TASK 78-31-41-820-801).
Subtask 78-31-52-440-053-A (1) Synchronize the thrust reverser actuators (Ref. AMM TASK 78-31-41-820-801).
C. Do the reactivation of the thrust reverser after nacelle maintenance (Ref. AMM TASK 78-30-00-440-807).
Subtask 78-31-52-863-050-A D. Pressurization of the Aircraft Hydraulic Systems
(1) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
(a) Pressurize the reservoir of the Green hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(b) Pressurize the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001).
(2) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
(a) Pressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(b) Pressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002).
(3) Bleed the thrust reverser hydraulic system:
(a) Do ten thrust reverser cycling test (Ref. AMM TASK 73-29-00-740-804).
(4) Do a visual check of leakage.
Subtask 78-31-52-410-053-A (1) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
(a) Pressurize the reservoir of the Green hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(b) Pressurize the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001).
(2) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
(a) Pressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(b) Pressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002).
(3) Bleed the thrust reverser hydraulic system:
(a) Do ten thrust reverser cycling test (Ref. AMM TASK 73-29-00-740-804).
(4) Do a visual check of leakage.