Removal of the Electrical Tertiary Lock Proximity Sensors [CFML]

TASK 78-37-52-000-802-A
Removal of the Electrical Tertiary Lock Proximity Sensors

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: 4134EG
FIN: 4135EG

1. Reason for the Job
This procedure gives the instructions to remove the proximity sensors from the tertiary lock proximity sensors.
There are two proximity sensors:

The channel A proximity sensor (4134EG) is in the lower position.
The channel B proximity sensor (4135EG) is in the upper position.

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	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL, 462AR

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
Tertiary Lock Proximity Sensors

3. Job Set-up
Subtask 78-37-52-941-052-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 a 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 78-37-52-010-055-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 78-37-52-040-052-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 78-37-52-010-056-A

D. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-806):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR

4. Procedure
Subtask 78-37-52-020-051-A

A. Removal of the Tertiary Lock Channel A Proximity Sensor
(1) Disconnect the electrical connector (8) from the solenoid (7) on the tertiary lock (9) (Ref. AMM TASK 70-70-00-910-804).
(2) Disconnect the channel A electrical connector (4134KS) (5) from the proximity sensor (4134EG) (3) (Ref. AMM TASK 70-70-00-910-804).
(3) Install the COVER - PROTECTION and CAP - PROTECTION on all the receptacles and connectors.
(4) Manually move the electrical harnesses (1) and (4) away from the removal path of the proximity sensor (4134EG) (3).
(5) Remove the two bolts (10) that attach the proximity sensor (4134EG) (3) to the tertiary lock (9).
(6) Remove the proximity sensor (4134EG) (3) from the tertiary lock (9).

Subtask 78-37-52-020-052-A

B. Removal of the Tertiary Lock Channel B Proximity Sensor
(1) Disconnect the electrical connector (8) from the solenoid (7) on the tertiary lock (9) (Ref. AMM TASK 70-70-00-910-804).
(2) Disconnect the channel B electrical connector (4135KS) (6) from the proximity sensor (4135EG) (2) (Ref. AMM TASK 70-70-00-910-804).
(3) Install the COVER - PROTECTION and CAP - PROTECTION on all the receptacles and connectors.
(4) Manually move the electrical harnesses (1) and (4) away from the removal path of the proximity sensor (4135EG) (2).
(5) Remove the two bolts (11) that attach the proximity sensor (4135EG) (2) to the tertiary lock (9).
(6) Remove the proximity sensor (4135EG) (2) from the tertiary lock (9).

[Rev.10 from 2021] 2026.04.01 03:37:28 UTC