Detailed Visual Inspection of the Hydraulic Control Unit [CFMB]

TASK 78-31-51-210-040-B
Detailed Visual Inspection of the Hydraulic Control Unit

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: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** 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	AR	ACCESS PLATFORM 1M(3 FT)
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR, 461AL, 462AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 451AL, 452AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 78-30-00-081-041-B	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-31-00-710-042-A	Operational Test of the Thrust Reverser System
TASK 78-31-51-000-042-A	Removal of the Hydraulic Control Unit
TASK 78-31-51-000-043-A	Removal of the Filter Clogging Indicator
TASK 78-31-51-400-042-A	Installation of the Hydraulic Control Unit
TASK 78-31-51-400-043-A	Installation of the Filter Clogging Indicator
TASK 78-31-51-920-001-A	Replacement of the Hydraulic Control Unit Filter
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-B	Closing of the Thrust Reverser Doors
Hydraulic Control Unit

3. Job Set-up
Subtask 78-31-51-941-053-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 78-31-51-010-056-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors: (Ref. AMM TASK 71-13-00-010-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL, 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL, 448AR.
(2) Put the ACCESS PLATFORM 1M(3 FT) in position.

Subtask 78-31-51-040-052-A ** ON A/C NOT FOR ALL

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

Subtask 78-31-51-010-057-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser doors: (Ref. AMM TASK 78-36-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
451AL, 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL, 462AR.

4. Procedure
Subtask 78-31-51-210-051-A ** ON A/C NOT FOR ALL

A. Do a visual inspection of the hydraulic control unit as follows:

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Examine the hydraulic control unit for:
A.Damage	No damage permitted	If you find some damage, replace the hydraulic control unit (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042).
B.Crack	No crack permitted	If you find a crack, replace the hydraulic control unit (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042).
C.Leakage	No leakage permitted	If there is leakage, check the coupling nuts and nipples for the correct torque (Ref. AMM TASK 78-31-51-400-042). If the leakage persists, replace the preformed packing (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042). If the leakage persists, replace the nipples (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042).
2.Examine the related hardware of the HCU for:
A.Damage	No damage permitted	If you find some damage, replace the defective part (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042).
3.Examine the clogging indicator for:
A.Indication	The indicator must not be extended	If the indicator is extended, replace the hydraulic filter and set the clogging indicator operational (Ref. AMM TASK 78-31-51-920-001). If the clogging indicator persists, replace the HCU filter clogging indicator (Ref. AMM TASK 78-31-51-000-043) and (Ref. AMM TASK 78-31-51-400-043). Then perform another operational check (Ref. AMM TASK 78-31-00-710-042). If the clogging indicator persists after operational check, replace HCU (Ref. AMM TASK 78-31-51-000-042) and (Ref. AMM TASK 78-31-51-400-042).
4.Examine the electrical Connectors for:
A.Tightness	The blue marks of the HCU connectors must be covered by the electrical harness connectors.	If the blue marks of the HCU connectors are visible, tighten the electrical harness connectors.

5. Close-up
Subtask 78-31-51-410-055-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) Close the thrust reverser doors: (Ref. AMM TASK 78-36-00-410-040).
(a) FOR [1000EM2] (ENGINE-2)
451AL, 452AR
(b) FOR [1000EM1] (ENGINE-1)
461AL, 462AR.
(3) Remove the access platform(s).

Subtask 78-31-51-440-053-A ** ON A/C NOT FOR ALL

B. Make the thrust reverser serviceable: (Ref. AMM TASK 78-30-00-081-041).

Subtask 78-31-51-410-056-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowl doors: (Ref. AMM TASK 71-13-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL, 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL, 448AR.
(2) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:25:36 UTC