Removal of the Manual Drive Unit (MDU) [CFML]

TASK 78-31-45-000-801-A
Removal of the Manual Drive Unit (MDU)

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.

ZONE: 400
FIN: 3041KM
FIN: 3042KM

1. Reason for the Job

NOTE: The left-hand lower actuator is also known as the synchronized non-locking actuator (3041KM).
The right-hand lower actuator is also known as the synchronized manual locking actuator (3042KM).

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

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M(3 FT)
No specific	AR	CAP - PROTECTION
No specific	1	CONTAINER 10 L(2 1/2 USGAL)
No specific	AR	COVER - PROTECTION
No specific	AR	WARNING NOTICE(S)
No specific	1	WRENCH - FLAT
No specific	1	WRENCH - TORQUE

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 78-30-00-040-807-A	Deactivation of the Thrust Reverser System for Nacelle Maintenance (ICU)
Manual Drive Unit (MDU)
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
TASK 29-10-00-864-001-A	Depressurize the Green Hydraulic System
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs

3. Job Set-up
Subtask 78-31-45-941-050-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) Put WARNING NOTICE(S) in position to tell persons not to operate:

The ENG/MODE selector switch
The ENG/MASTER 1(2) control switch.

(2) On the ENG section of maintenance panel 50VU:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).

Subtask 78-31-45-010-050-A

B. Get Access
(1) Open the fan cowl doors (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) Put an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 78-31-45-040-050-A

C. Deactivation of the Thrust Reverser System for Maintenance

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) Do the deactivation of the thrust reverser system for nacelle maintenance (Ref. AMM TASK 78-30-00-040-807).

Subtask 78-31-45-864-050-A

D. Depressurization of the Hydraulic System
(1) Put a WARNING NOTICE(S) 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) Depressurize the Green hydraulic system (Ref. AMM TASK 29-10-00-864-001).
(b) Depressurize the reservoir of the Green hydraulic system (Ref. AMM TASK 29-14-00-614-001).
(3) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
(a) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).
(b) Depressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-001).

4. Procedure
Subtask 78-31-45-020-050-A

A. Removal of the Manual Drive Unit (MDU)

Manual Drive Unit (MDU)

WARNING: USE PERSONAL PROTECTIVE EQUIPMENT WHEN YOU DO WORK ON THE HYDRAULIC THRUST REVERSER ACTUATION SYSTEM (TRAS). HYDRAULIC FLUID CAN CAUSE INJURY TO PERSONS AND DAMAGE TO ENGINE PARTS.

CAUTION: DO NOT LET HYDRAULIC FLUID FALL ON THE ENGINE OR THE THRUST REVERSER. 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.

(1) Put the CONTAINER 10 L(2 1/2 USGAL) in position below the left lower actuator (1).
(2) Remove the MDU.

CAUTION: HOLD THE ACTUATOR FITTING WHILE YOU TURN THE MDU. IF THE ACTUATOR FITTING BECOMES LOOSE, THE ACTUATOR WILL BE UNSERVICEABLE.

(a) Use a WRENCH - TORQUE to hold the fitting on the left lower actuator (1) while you disconnect the MDU (2). Use a second WRENCH - FLAT to remove the MDU from the left lower actuator (1).
(3) Let the hydraulic fluid drain into the CONTAINER 10 L(2 1/2 USGAL).
(4) Remove the CONTAINER 10 L(2 1/2 USGAL).
(5) Put the CONTAINER 10 L(2 1/2 USGAL) in position below the right lower actuator (4).
(6) Remove the MDU.

CAUTION: HOLD THE ACTUATOR FITTING WHILE YOU TURN THE MDU. IF THE ACTUATOR FITTING BECOMES LOOSE, THE ACTUATOR WILL BE UNSERVICEABLE.

(a) Use a WRENCH - TORQUE to hold the fitting on the right lower actuator (4) while you disconnect the MDU (3). Use a WRENCH - FLAT to remove the MDU from the right lower actuator (4).
(7) Let the hydraulic fluid drain into the CONTAINER 10 L(2 1/2 USGAL).
(8) Remove the CONTAINER 10 L(2 1/2 USGAL).
(9) Install COVER - PROTECTION and CAP - PROTECTION on all the open ports, open tubes, open hoses and disconnected connectors.

[Rev.10 from 2021] 2026.04.01 13:13:28 UTC