Removal of the Electrical Tertiary Lock System [CFML]

TASK 78-37-51-000-805-A
Removal of the Electrical Tertiary Lock System

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.

FIN: 4005EG

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

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
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 78-32-50-010-801-A	Manually Deploy the Translating Cowl
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
Electrical Tertiary Lock System

3. Job Set-up
Subtask 78-37-51-941-073-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, and
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 78-37-51-010-093-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

Subtask 78-37-51-040-064-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).

Subtask 78-37-51-010-094-A

D. Manually deploy the translating cowl approximately 5 in. (127.00 mm) (Ref. AMM TASK 78-32-50-010-801).

Subtask 78-37-51-010-099-A

E. Opening of the left thrust reverser cowl-door

CAUTION: DO NOT OPEN THE THRUST REVERSER IF YOU CANNOT STOW THE TRANSLATING COWL, AND THE TRANSLATING COWL IS DEPLOYED MORE THAN 10 INCHES (254 MM). IF YOU DO, THE TRANSLATING COWL CAN HIT THE WING AND CAUSE DAMAGE TO EQUIPMENT.

(1) Open the left thrust reverser cowl-doors (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

4. Procedure
Subtask 78-37-51-020-064-A

A. Removal of the Electrical Tertiary Lock System (9)
(1) Disconnect the electrical connectors on the electrical harnesses (1) and (4) from the tertiary lock system (9) as follows (Ref. AMM TASK 70-70-00-910-804):

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

(a) Disconnect the electrical connector (6) from the proximity sensor (2).
(b) Disconnect the electrical connector (5) from the proximity sensor (3).
(c) Disconnect the electrical connector (8) from the solenoid (7).
(d) Manually move the electrical cables (1) and (4) away from of the removal path of the tertiary lock system (9).
(2) Remove the four bolts (10) that attach the tertiary lock system (9) to the thrust reverser.

NOTE: It is necessary to hold the tertiary lock system (9) in place when removing the four bolts to prevent damage to the surrounding area.

(3) If necessary to get better access for the tertiary lock system (9) removal you can pull the electrical harnesses (1) and (4) out of the spring clips.
(4) Carefully pull the tertiary lock system (9) away from the thrust reverser.
(5) Install the COVER - PROTECTION and CAP - PROTECTION on all the openings, tubes, hoses and connectors.

[Rev.10 from 2021] 2026.04.01 03:37:26 UTC