Installation of the Thrust Reverser Actuation System (TRAS) Hydraulic Control Unit (HCU) [PW11]

TASK 78-31-01-400-801-A
Installation of the Thrust Reverser Actuation System (TRAS) Hydraulic Control Unit (HCU)

WARNING: WEAR APPLICABLE PERSONAL PROTECTIVE EQUIPMENT (PPE) WHEN YOU DO THIS TASK. BEFORE YOU USE PPE, READ, UNDERSTAND AND OBEY ALL INSTRUCTIONS FOR ITS USE. THESE INSTRUCTIONS INCLUDE INSTRUCTIONS FROM THE MANUFACTURER, YOUR EMPLOYER AND GOVERNMENT REGULATIONS. YOU CAN GET INJURED IF YOU DO NOT USE PPE. GET INSTRUCTIONS FROM YOUR EMPLOYER ON WHICH PPE IS NECESSARY.

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AND THE ADJACENT COMPONENTS AFTER ENGINE SHUTDOWN. THE ENGINE, THE ENGINE OIL AND THE ADJACENT COMPONENTS CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

ZONE: 400
FIN: 4310EG1 ** ON A/C NOT FOR ALL
FIN: 4310EG2 ** ON A/C NOT FOR ALL

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)
No specific	AR	COVER - PROTECTION
No specific	1	OHMMETER MULTIRANGE
No specific	1	PLIERS - NOSE, SOFT, LONG
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 44.2 and 26.5 lbf.in (0.50 and 0.30 m.daN )
No specific	Torque wrench: range to between 93.8 and 72.5 lbf.in (1.06 and 0.82 m.daN )
No specific	Torque wrench: range to between 283.2 and 256.7 lbf.in (3.20 and 2.90 m.daN )
No specific	Torque wrench: range to between 522 and 478 lbf.in (5.90 and 5.40 m.daN )
No specific	Torque wrench: range to between 734.6 and 663.8 lbf.in (8.30 and 7.50 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.PU1-0001)	cloth
(Material No.PU1-0006)	abrasive pad
(Material No.PU2-0001)	alcohol, isopropyl
(Material No.PU6-0003)	lubricant
(Material No.04TMB2)	Varnish-- Electrical Bonding Structure

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AT
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AT

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
2	PIN	AIPC 78-36-86-02-010

E. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-860-832-A	Procedure to Prevent Engine Motoring and to Stop the Electrical Supply to the EEC
TASK 73-25-34-400-802-A	Installation of the Engine Interface Unit (EIU)
TASK 78-31-00-710-805-A	Operational Test of Thrust Reverser with MCDU
TASK 78-31-00-710-805-A-01	Thrust Reverser Cycling Test (Engine Running)
TASK 78-31-06-820-801-A	Adjustment of the Inhibit Cable
Thrust Reverser Actuation System (TRAS) Hydraulic Control Unit (HCU)
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 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
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, ENG 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
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)

3. Job Set-up
Subtask 78-31-01-941-051-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Make sure that you did the procedure to prevent engine motoring and to stop the electrical supply to the Electronic Engine Control (EEC)
(Ref. AMM TASK 71-00-00-860-832).

Subtask 78-31-01-865-051-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
121VU	DCV B/ENG1 PWR SUPPLY	103KS1	K44
121VU	DCV A/ENG1 PWR SUPPLY	102KS1	K42
121VU	ICU A/ENG1 PWR SUPPLY	22KS1	R39
** ON A/C NOT FOR ALL
121VU	ICU B/ENG1 PWR SUPPLY	101KS1	R42
** ON A/C NOT FOR ALL
121VU	DCV A/ENG1 PWR SUPPLY	102KS1	N44
121VU	DCV B/ENG1 PWR SUPPLY	103KS1	Q44
121VU	ICU A/ENG1 PWR SUPPLY	22KS1	R38
** ON A/C NOT FOR ALL
FOR FIN: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
121VU	DCV B/ENG2 PWR SUPPLY	103KS2	K45
121VU	DCV A/ENG2 PWR SUPPLY	102KS2	K43
121VU	ICU A/ENG2 PWR SUPPLY	22KS2	R40
** ON A/C NOT FOR ALL
121VU	ICU B/ENG2 PWR SUPPLY	101KS2	R43
** ON A/C NOT FOR ALL
121VU	DCV A/ENG2 PWR SUPPLY	102KS2	N45
121VU	DCV B/ENG2 PWR SUPPLY	103KS2	Q45
121VU	ICU A/ENG2 PWR SUPPLY	22KS2	R39

Subtask 78-31-01-864-051-A ** ON A/C NOT FOR ALL

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, ENG 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, ENG 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 78-31-01-010-051-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Make sure that the ACCESS PLATFORM 2M (6 FT) is in position.
(2) Make sure that the pylon access panel is removed:
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AT
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AT

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 78-31-01-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Hydraulic Control Unit (HCU)

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES. WORK ON THE HYDRAULIC SYSTEMS CAN BE DANGEROUS.

WARNING: DO NOT TOUCH THE HYDRAULIC SYSTEM COMPONENTS UNTIL THEY ARE COOL. THE ENGINE COMPONENTS STAY HOT FOR MORE TIME AND CAN CAUSE INJURY.

WARNING: YOU MUST NOT GET HYDRAULIC FLUID ON YOUR SKIN, IN YOUR EYES OR IN YOUR MOUTH. THE HYDRAULIC FLUID IS POISONOUS AND CAN BE ABSORBED INTO YOUR BODY. IF YOU ACCIDENTALLY GET HYDRAULIC FLUID IN YOUR EYES, MOUTH OR ON YOUR SKIN, FLUSH WITH WATER AND GET MEDICAL AID.

CAUTION: YOU MUST NOT LET HYDRAULIC FLUID FALL ON THE ENGINE. UNWANTED HYDRAULIC FLUID MUST BE REMOVED IMMEDIATELY WITH A CLEAN LINT- FREE CLOTH. THE HYDRAULIC FLUID CAN CAUSE DAMAGE TO THE SURFACE PROTECTION AND SOME PARTS.

(1) Removal of the protection covers

CAUTION: REMOVE THE PROTECTION COVERS FROM THE OPENINGS AS NECESSARY TO PREVENT ENGINE DAMAGE.

(a) Make sure that you remove the COVER - PROTECTION as necessary to prevent damage to the engine.
(2) Clean the bottom surface of the TRAS HCU (1) with the abrasive pad (Material No.PU1-0006) . Clean the surface of the HCU (1) with the clean cloth (Material No.PU1-0001) made wet with the PU2-0001alcohol, isopropyl or equivalent. Remove the alcohol before it dries with the clean cloth (Material No.PU1-0001) .
(3) Clean the bracket on the pylon with the abrasive pad (Material No.PU1-0006) . Clean the bracket with the clean cloth (Material No.PU1-0001) made wet with the PU2-0001alcohol, isopropyl or equivalent. Remove the alcohol before it dries with the clean cloth (Material No.PU1-0001) .
(4) Clean the surface of the bolt and the washer:

CAUTION: DO NOT RUB THE BOLT THREADS WITH THE SCOTCH-BRITE PAD. THIS CAN CAUSE DAMAGE TO THE THREADS.

(a) Clean the surfaces of a bolt (4) and a washer (5) with the abrasive pad (Material No.PU1-0006) . Clean the surfaces of the bolt (4) and the washer (5) with the clean cloth (Material No.PU1-0001) made wet with the PU2-0001alcohol, isopropyl or equivalent. Remove the alcohol before it dries with the clean cloth (Material No.PU1-0001) .
(5) Install the HCU (1) on the bracket on the pylon.
(a) Install the bolt (4) and the washer (5) that you cleaned in the aft hole on the right side of the HCU (1).
(b) Install the other three bolts (4) and the other three washers (5) to the other three holes on the HCU (1).
(c) TORQUE the bolts (4) to between 93.8 and 72.5 lbf.in (1.06 and 0.82 m.daN )

.
(6) Use the OHMMETER MULTIRANGE to measure the resistance between the HCU (1) and the bracket on the pylon.
(a) Make sure that it is not more than 0.010 ohms.
(b) If the resistance is more than 0.010 ohms, remove the HCU (1) and repeat steps 4.A.(1) thru 4.A.(5) again.
(7) Put a layer of the Varnish-- Electrical Bonding Structure (Material No.04TMB2) on the bolt (4) and the washer (5) in the aft hole on the right side of the HCU (1).
(8) Connect the electrical and the hydraulic connections.
(a) Remove the CAP - BLANKING from the channel B Direction Control Unit (DCU) proximity sensor harness.
(b) Connect the channel B DCU proximity sensor harness to the HCU (1) and tighten the connector with your fingers.
(c) Tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(d) Remove the CAP - BLANKING from the channel A DCU proximity sensor harness.
(e) Connect the channel A DCU proximity sensor harness to the HCU (1) and tighten the connector with your fingers.
(f) Tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(g) Remove the CAP - BLANKING from the Isolation Control Unit (ICU) coil harness.
(h) Connect the ICU coil harness to the HCU (1) and tighten the connector with your fingers.
(i) Tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(j) Connection of the line:

CAUTION: HYDRAULIC FLUID CAN CAUSE DAMAGE TO EQUIPMENT. IF HYDRAULIC FLUID FALLS ON A SURFACE, IMMEDIATELY CLEAN THE SURFACE WITH A CLEAN CLOTH.

1 Remove the PLUG - BLANKING from the stow line, deploy line, right return line, supply line and aft return line on the pylon.
2 Apply a thin layer of the lubricant (Material No.PU6-0003) or equivalent to the threads of the coupling nuts on these lines.
3 Connect the stow line to the stow port on the right side of the HCU (1).
4 TORQUE the coupling nut on the stow line to between 522 and 478 lbf.in (5.90 and 5.40 m.daN )

.
5 Connect the deploy line to the deploy port on the right side of the HCU (1).
6 TORQUE the coupling nut on the deploy line to between 734.6 and 663.8 lbf.in (8.30 and 7.50 m.daN )

.
7 Connect the right return line to the return port on the right side of the HCU (1).
8 TORQUE the coupling nut on the return line to between 283.2 and 256.7 lbf.in (3.20 and 2.90 m.daN )

.
(k) Remove the CAP - BLANKING from the DCU coil harness.
(l) Connect the DCU coil harness to the HCU (1) and tighten the connector with your fingers.
(m) Tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(n) Attach the upper inhibit cable to the HCU (1) with the nut (3).
(o) TORQUE the nut (3) to between 44.2 and 26.5 lbf.in (0.50 and 0.30 m.daN )

WARNING: USE PROTECTIVE GOGGLES WHEN YOU REMOVE OR INSTALL A COTTER PIN. EACH TIME YOU REMOVE A COTTER PIN DURING THE TASK, DISCARD IT IMMEDIATELY. A LOOSE COTTER PIN CAN CUT YOU OR MAKE YOU BLIND.

(p) Safety the nut (3) with the new AIPC 78-36-86-02-010 PIN (2).
(q) Connect the supply line to the supply port on the aft end of the HCU (1).
(r) TORQUE the coupling nut on the supply line to between 522 and 478 lbf.in (5.90 and 5.40 m.daN )

.
(s) Connect the aft return line to the return port on the aft end of the HCU (1).
(t) TORQUE the coupling nut on the return line to between 734.6 and 663.8 lbf.in (8.30 and 7.50 m.daN )

.
(u) Remove the CAP - BLANKING from the channel A ICU proximity sensor harness.
(v) Connect the channel A ICU proximity sensor harness to the HCU (1) and tighten the connector with your fingers.
(w) Tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(x) Remove the CAP - BLANKING from the channel B ICU proximity sensor harness.
(y) Connect the channel B ICU proximity sensor harness to the HCU (1) and tighten the connector with your fingers. Then tighten the connector 1/8 to 1/4 of a turn more with the PLIERS - NOSE, SOFT, LONG.
(z) Adjust the inhibit cable (Ref. AMM TASK 78-31-06-820-801).

5. Close-up
Subtask 78-31-01-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel on the pylon:
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
413AT
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
423AT
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

Subtask 78-31-01-865-052-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 1000EM1 (ENGINE1)
121VU	DCV B/ENG1 PWR SUPPLY	103KS1	K44
121VU	DCV A/ENG1 PWR SUPPLY	102KS1	K42
121VU	ICU A/ENG1 PWR SUPPLY	22KS1	R39
** ON A/C NOT FOR ALL
121VU	ICU B/ENG1 PWR SUPPLY	101KS1	R42
** ON A/C NOT FOR ALL
121VU	DCV A/ENG1 PWR SUPPLY	102KS1	N44
121VU	DCV B/ENG1 PWR SUPPLY	103KS1	Q44
121VU	ICU A/ENG1 PWR SUPPLY	22KS1	R38
** ON A/C NOT FOR ALL
FOR FIN: 1000EM2 (ENGINE2)
121VU	DCV B/ENG2 PWR SUPPLY	103KS2	K45
121VU	DCV A/ENG2 PWR SUPPLY	102KS2	K43
121VU	ICU A/ENG2 PWR SUPPLY	22KS2	R40
** ON A/C NOT FOR ALL
121VU	ICU B/ENG2 PWR SUPPLY	101KS2	R43
** ON A/C NOT FOR ALL
121VU	DCV A/ENG2 PWR SUPPLY	102KS2	N45
121VU	DCV B/ENG2 PWR SUPPLY	103KS2	Q45
121VU	ICU A/ENG2 PWR SUPPLY	22KS2	R39

Subtask 78-31-01-863-050-A ** ON A/C NOT FOR ALL

C. Pressurization of the Aircraft Hydraulic Systems
(1) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
(a) Pressurize the reservoir of the Green hydraulic system (Ref. AMM TASK 29-14-00-614-002).
(2) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(a) Pressurize the reservoir of the Yellow hydraulic system (Ref. AMM TASK 29-14-00-614-002).

Subtask 78-31-01-710-050-A ** ON A/C NOT FOR ALL

D. Make sure that all the circuit breakers shown in the paragraph Procedure of the engine interface unit installation are closed. If they are not, close them in the recommended sequence
(Ref. AMM TASK 73-25-34-400-802).
(1) Do the operational test of the thrust reverser with the Multipurpose Control and Display Unit (MCDU) (bleeding) (Ref. AMM TASK 78-31-00-710-805).

[Rev.10 from 2021] 2026.04.01 07:52:45 UTC