Removal of the Thrust Reverser Actuation System Electrical Harnesses [CFML]

TASK 71-51-43-000-806-A
Removal of the Thrust Reverser Actuation System Electrical Harnesses

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: 4767EG
FIN: 4768EG
FIN: 4769EG
FIN: 4770EG
FIN: 4773EG
FIN: 4774EG

1. Reason for the Job
A. This procedure gives the instructions to remove a set of six electrical harnesses from the thrust reverser.
B. The set of harnesses connect to components of the Hydraulic Thrust Reverser Actuation System (HTRAS). The harnesses connect to the electrical Tertiary Lock System (TLS), the Primary Locking System (PLS) on the Left Hand (LH) Self-Locking Feedback Actuator (SLFA), the Directional Control Unit (DCU) and the Pylon Junction Box (PJB).
C. The set includes the six harnesses that follow:

DCU Channel A Harness (4767EG)
DCU Channel B Harness (4768EG)
TLS Power Harness (PJB to LH Break) (4773EG)
TLS Power Harness (LH Break to TLS) (4774EG)
Pylon PLS/TLS Channel A and B Harness (LH Break to LH SLFA) (4769EG)
Pylon PLS/TLS Channel A and B Harness (LH Break to RH Break) (4770EG).

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	1	PLIERS - JAWED, SOFT
No specific	AR	WARNING NOTICE(S)

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, 451AL
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL

C. Referenced Information

REFERENCE	DESIGNATION
TASK 70-70-00-910-804-A	Electrical Standard Practices
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)
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
Thrust Reverser Actuation System Electrical Harnesses

3. Job Set-up
Subtask 71-51-43-941-078-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 71-51-43-010-095-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.

Subtask 71-51-43-040-050-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).

4. Procedure
Subtask 71-51-43-020-085-A

A. Removal of the Thrust Reverser Actuation System Electrical Harnesses Disconnected Connectors

NOTE: If necessary use PLIERS - JAWED, SOFT to disconnect the electrical connectors.

(1) Before you remove the harnesses, make a record of the harness routing to help during installation.
(2) Remove the electrical connectors on the right side of the engine as follows (Ref. AMM TASK 70-70-00-910-804):
(a) Disconnect the electrical connector (77) from the interface bracket (78).
(b) Disconnect the electrical connector (79) from the interface bracket (78).
(c) Disconnect the electrical connector (72) from the interface bracket (71).
(d) Disconnect the electrical connector (73) from the interface bracket (71)
(e) Disconnect the electrical connector (70) from the pylon junction box (65).
(3) Remove the bolt (76) that attaches the harness clamp (75) to the support bracket (74).
(4) Remove the two bolts (66) and the two bolts (68) that attach the two harness clamps (67) and (69) from the pylon junction box (65).
(5) Push the upper ends of the harnesses through the opening between the pylon and the top of the engine.
(6) Move the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE to the left side of the engine.
(7) Remove the two bolts (57) and the two bolts (58) that attach the two harness clamps (56) and (59) from the support brackets (55) and (60).
(8) Carefully pull the upper ends of the harnesses through the opening below the pylon to the left side of the engine.
(9) Remove the bolts (40) and (53) that attach the P-clamps (41) and (54) to the support bracket (42).
(10) Remove the harness clamp (51).
(11) Disconnect the harness (50) electrical connectors (49) and (52) from the support bracket (42) (Ref. AMM TASK 70-70-00-910-804).
(12) Remove the four nuts (45) and screws (47) that attach the electrical connector (46) from the support bracket (42).
(13) Remove the four nuts (44) and screws (48) that attach the electrical connector (43) from the support bracket (42).
(14) Remove the bolt (37) that attaches the bar clamp (38) to the support bracket (31).
(15) Disconnect the electrical connector (34) from the Directional Control Unit (DCU) connection (33) on the DCU (36) (Ref. AMM TASK 70-70-00-910-804).
(16) Disconnect the electrical connector (35) from the DCU connection (32) on the DCU (36) (Ref. AMM TASK 70-70-00-910-804).
(17) Disconnect the harness (3) from the actuator (27) as follows (Ref. AMM TASK 70-70-00-910-804):
(a) Disconnect the electrical connector (29) from the mating receptacle on the Linear Variable Differential transducer (LVDT) (26).
(b) Disconnect the electrical connector (25) from the mating receptacle on the prox sensor (24).
(c) Disconnect the electrical connector (23) from the mating receptacle on the prox sensor (28).
(18) Open the left thrust reverser cowl door (Ref. AMM TASK 78-36-00-010-806).
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL
(19) Remove the parts from the latch beam as follows:
(a) Remove the bolt (17) that attach the bar clamps (18) to the support bracket (16).
(b) Remove the bolt (20) that attach the bar clamp (19) to the latch beam (15).
(c) Remove the harness (3) from the spring clips (22) and (21).
(20) Remove the four bolts (4) that attach the harness bracket (5) to the support bracket (6).
(21) Remove the parts from the TLS as follows (Ref. AMM TASK 70-70-00-910-804):
(a) Disconnect the electrical connector (8) from the prox sensor (2).
(b) Disconnect the electrical connector (7) from the prox sensor (9).
(c) Disconnect the electrical connector (11) from the TLS (10).
(22) Carefully pull the harness (3) out of the spring clips on the support bracket (12).
(23) Carefully pull the harness out of the spring clips on the 15 support brackets (1) on the left side of the thrust reverser.
(24) Remove the harness bundle from the engine.
(25) Make a record of the location and position of the P-clamps, bar clamps and harness clamps on the set of harnesses (3) to help during installation.
(26) At a workbench, disassemble the P-clamps, bar clamps and harness clamps from each of the six harnesses.
(27) Install CAP - PROTECTION on all the disconnected connectors.

[Rev.10 from 2021] 2026.04.01 12:58:19 UTC