Removal of the Yellow HCU Pipe

TASK 29-13-49-000-049-A
Removal of the Yellow HCU Pipe

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

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: 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.

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.

CAUTION: USE A SECOND WRENCH TO APPLY COUNTERTORQUE TO THE UNION WHEN YOU DISCONNECT/CONNECT HYDRAULIC LINES ON UNIONS. IF YOU DO NOT USE THE SECOND WRENCH, THERE IS A RISK THAT YOU WILL LOOSEN OR TIGHTEN THE UNION TOO MUCH.

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

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE
No specific	1	CAP - BLANKING
No specific	AR	CONTAINER 5 L (1.32 USGAL)
No specific	1	PLIERS - NOSE, SOFT, LONG
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM2] (ENGINE-2)
423AL, 447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 26-21-49-000-002-A	Removal of the Engine Fire-Extinguishing Pipe
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 29-13-49-000-009-A	Removal of the Engine 2 Thrust-Reverser Hydraulic-Supply Hoses
TASK 29-14-00-614-001-A	Depressurization of the Hydraulic Reservoirs
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-11-000-041-A	Removal of the Fan Cowl Doors
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-37-51-000-004-A	Removal of the Thrust Reverser Hydraulic Filter Assembly
HCU Pipe ** ON A/C NOT FOR ALL
HCU Pipe ** ON A/C NOT FOR ALL
Support Plate

3. Job Set-up
Subtask 29-13-49-860-106-B ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) Depressurize the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002).
(3) Depressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-001).

Subtask 29-13-49-941-099-B ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) Make sure that the engine 2 shutdown occurred not less than five minutes before you do this procedure.
(2) On AIR COND panel 30VU:

Make sure that the APU BLEED pushbutton switch is released (the ON legend off).
Put a WARNING NOTICE(S) in position to tell persons not to operate this pushbutton switch.

(3) Put a WARNING NOTICE(S) in position to tell persons not to pressurize the Yellow hydraulic system:

On the HYD section of overhead panel 40VU
On the ground service panel 198CB.

(4) Put a WARNING NOTICE(S) in position on access door 195BB to tell persons not to pressurize the reservoir of the Yellow hydraulic system.
(5) On the center pedestal, on ENG panel 115VU:

Make sure that the ENG/MODE selector switch is in the NORM position.
Make sure that the ENG/MASTER 2 control switch was in the OFF position not less than five minutes before you do this procedure.
Put WARNING NOTICE(S) in position to tell persons not to operate the ENG/MODE selector switch and the ENG/MASTER 2 control switch.

(6) On the ENG section of maintenance panel 50VU:

Make sure that the ON legend of the ENG FADEC GND PWR/2 pushbutton switch is off.
Put a WARNING NOTICE(S) in position to tell persons not to energize the FADEC 2.

Subtask 29-13-49-865-093-A ** ON A/C NOT FOR ALL

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

Subtask 29-13-49-010-097-B ** ON A/C NOT FOR ALL

D. Get Access
(1) Remove the access panel:
(a) FOR [1000EM2] (ENGINE-2)
423AL.
(2) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(a) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
(3) Put an ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE in position at the zone 420.
(4) Put a CONTAINER 5 L (1.32 USGAL) in position below the hydraulic lines.

Subtask 29-13-49-040-064-B ** ON A/C NOT FOR ALL

E. Deactivation of the Thrust Reverser

WARNING: MAKE SURE THAT THE THRUST REVERSER HYDRAULIC CONTROL UNIT (HCU) IS DEACTIVATED BEFORE YOU DO WORK ON OR AROUND THE THRUST REVERSER. IF THE HCU IS NOT DEACTIVATED, THERE IS A RISK OF UNWANTED THRUST REVERSER OPERATION WHICH CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Make the thrust reverser unserviceable for maintenance (Ref. AMM TASK 78-30-00-481-041).

Subtask 29-13-49-010-098-B ** ON A/C NOT FOR ALL

F. Get Access
(1) Open the thrust reverser doors (Ref. AMM TASK 78-36-00-010-040):
(a) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 29-13-49-020-105-D ** ON A/C NOT FOR ALL

G. Get Access to the Yellow HCU Pipe
(1) Remove the left fan-cowl door (Ref. AMM TASK 71-13-11-000-041).
(2) Disconnect the electrical connector from the thrust-reverser hydraulic isolation-valve.

HCU Pipe ** ON A/C NOT FOR ALL

(a) Disconnect the electrical connector (36) from the thrust-reverser isolation-valve (33).

NOTE: If necessary, use the PLIERS - NOSE, SOFT, LONG to loosen the electrical connector.

(b) Put CAP - BLANKING on the electrical connector of the harness and on the isolation valve.
(3) Disconnect the thrust-reverser hydraulic-supply hoses (Ref. AMM TASK 29-13-49-000-009).
(a) On the left interface bracket, disconnect the four hoses.
(b) At the left bracket, disconnect the hose from the pylon tube.
(c) Release the clamps that hold the five disconnected hoses.
(d) Push the five hoses into the pylon.
(4) Release the left and the right support plates in the pylon.

Support Plate ** ON A/C NOT FOR ALL

(a) Remove the bolts (3), the washers (2) and the nuts (1) that attach the plate (5) to the structure (4).
(b) Discard the nuts (1).
(5) Disconnect the two FWD parts of the engine fire-extinguishing pipe (Ref. AMM TASK 26-21-49-000-002).

NOTE: It is not necessary to remove the left thrust-reverser half.

(a) Remove the bolts, the washers and the nuts that attach the two FWD parts of the pipe.
(b) Disconnect the two FWD parts from the other parts of the engine fire-extinguishing pipe and put them down on the fan case.

NOTE: Do not disconnect the two FWD parts of the engine fire-extinguishing pipe from each other.

(6) Remove the return pipe.

HCU Pipe ** ON A/C NOT FOR ALL

(a) Remove the bolt (21), the washer (22) and the nut (18) from the clamp (20).
(b) Discard the nut (18).
(c) Remove the bolt (28) and the washer (29) from the clamp (30).
(d) Disconnect the return pipe (27) from the thrust-reverser hydraulic isolation-valve (33) and from the case drain pipe (1).
(e) Put the PLUG-BLANKING in each disconnected line end.
(f) Remove the return pipe (27) from the pylon.
(7) Remove the control pipe.

HCU Pipe ** ON A/C NOT FOR ALL

(a) Remove the bolt (8) and the washer (9) from the clamp (10).
(b) Remove the bolt (24), the washer (23) and the nut (19) from the clamp (25).
(c) Discard the nut (19) and keep the support (26).
(d) Disconnect the nut (2) from the union (5).
(e) Remove the bolts (4) and the washers (3) from the union (5).
(f) Disconnect the control pipe (7) from the thrust-reverser hydraulic isolation-valve (33).
(g) Put the PLUG-BLANKING in each disconnected line end.
(h) Remove the control pipe (7) from the pylon.
(8) Remove the thrust-reverser hydraulic filter-assembly (Ref. AMM TASK 78-37-51-000-004).

4. Procedure
Subtask 29-13-49-020-106-B ** ON A/C NOT FOR ALL

A. Removal of the Yellow HCU Pipe
(1) Remove the bolt (17) and the washer (16) from the clamp (15).

NOTE: The bolt (17) and the washer (16) are removed from the clamp (13) in the step 3.G.(8).

(2) Disconnect the HCU pipe (14) from the pressure pipe (32).
(3) Remove the HCU pipe (14) from the pylon.

NOTE: The nut (12) is disconnected from the hydraulic filter canister (11) in the step 3.G.(8).

(4) Put the PLUG-BLANKING in each disconnected line end.

Subtask 29-13-49-020-106-C ** ON A/C NOT FOR ALL

A. Removal of the Yellow HCU Pipe
(1) Remove the bolts (17) and the washers (16) from the clamps (15).

NOTE: The bolt (17) and the washer (16) are removed from the clamp (13) in the step 3.G.(8).

(2) Disconnect the HCU pipe (14) from the pressure pipe (32).
(3) Remove the HCU pipe (14) from the pylon.

NOTE: The nut (12) is disconnected from the hydraulic filter canister (11) in the step 3.G.(8).

(4) Put the PLUG-BLANKING in each disconnected line end.

[Rev.10 from 2021] 2026.04.01 00:22:43 UTC