Removal of the Isolation Control Unit (ICU) [CFML]

TASK 78-31-51-000-804-A
Removal of the Isolation Control Unit (ICU)

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.

ZONE: 400

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	CAP - PROTECTION
No specific	AR	COVER - PROTECTION
No specific	1	MAT - PROTECTIVE
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CPNCL02069)	Textile - lint free cotton
(Material No.CPNCL02662)	Isopropyl alcohol

C. 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

D. Referenced Information

REFERENCE	DESIGNATION
TASK 54-52-11-000-807-A	Removal of the Access Skin Panels
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 78-30-00-040-809-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-31-49-680-801-A	Draining of the Thrust Reverser Hydraulic Tubes
ICU
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 78-31-51-941-076-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 a 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 78-31-51-010-095-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 2M (6 FT) - ADJUSTABLE in position below the fan cowl door.

Subtask 78-31-51-864-062-A

C. 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).

Subtask 78-31-51-040-077-A

D. 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 maintenance (Ref. AMM TASK 78-30-00-040-809).

Subtask 78-31-51-680-050-A

E. Drain the thrust reverser hydraulic tubes attached to the actuator (Ref. AMM TASK 78-31-49-680-801).

Subtask 78-31-51-410-083-A

F. Close Access
(1) 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

Subtask 78-31-51-010-105-A

G. Get Access
(1) Remove the forward pylon fairing (2) with screws (1) from the engine nacelle (Ref. AMM TASK 54-52-11-000-807). Keep the access platform from the fairing removal procedure in position at the pylon.

4. Procedure

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 78-31-51-020-064-A

A. Removal of the ICU
(1) Disconnect the hydraulic tube (4) from the engine pylon as follows:
(a) Loosen the coupling nut to disconnect the hydraulic tube (4) from the ICU (3).
(b) Remove sealant from cavity.
(2) 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
(3) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position under the right fan cowl door.
(4) Install a MAT - PROTECTIVE under the ICU (3) to prevent damage to the engine.
(5) Disconnect electrical connectors (7) and (8) from the ICU (3) (Ref. AMM TASK 70-70-00-910-804).
(6) Disconnect the supply tube (10) from the ICU (3) as follows:
(a) Loosen the coupling nut to disconnect the supply tube (10) from the ICU (3).
(7) Disconnect the return tube (9) from the ICU (3) as follows:
(a) Loosen the coupling nut to disconnect the return tube (9) from the ICU (3).
(8) Remove the ICU (3) as follows:
(a) Loosen, but do not remove the four bolts (12) that attach the plate (11) to the pylon.
(b) Slide the plate (11) to get better access. The slots in the plate (11) where the four bolts (12) are installed permit forward and aft movement of the plate (11).
(c) Remove the two bolts (12) and washers (13) that attach the right side of the plate (11) to the pylon.
(d) Hold the ICU (3) and remove the two bolts (12) and washers (13) that attach the left side of the plate (11) to the pylon.
(e) Remove the plate (11) with the ICU (3) attached from the pylon.
(f) With the ICU (3) removed from the pylon, remove four bolts (6) to remove the plate (11) from the ICU (3).
(g) Clean unnecessary sealant remains from parts with clean Textile - lint free cotton (Material No.CPNCL02069) and Isopropyl alcohol (Material No.CPNCL02662) .
(9) Install COVER - PROTECTION and CAP - PROTECTION on all open ports, open tubes, open hoses and connectors.
(10) Remove and discard the packing (5).

[Rev.10 from 2021] 2026.04.01 03:35:29 UTC