Deactivation of the Electrical Tertiary Lock System [CFML]

TASK 78-37-00-040-803-A
Deactivation 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.

1. Reason for the Job
MMEL 78-30-04B
THRUST REVERSER DOOR TERTIARY LOCK
A. This procedure gives the instructions to do a deactivation of the tertiary lock system. This procedure sets the tertiary lock system in the UNLOCKED condition.
B. Do this procedure only during nacelle maintenance, and only when specified by another task.
C. After the deactivation procedure, you can manually stow or deploy the thrust reverser.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
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
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-803-A	Closing 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
TASK 78-36-00-410-806-A	Closing of the Thrust Reverser Cowl Doors
Electrical Tertiary Lock System

3. Job Set-up
Subtask 78-37-00-941-053-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) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).

Subtask 78-37-00-010-051-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 78-37-00-040-055-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 78-37-00-010-052-A

D. Open the thrust reverser 6 o'clock aft access door (Ref. AMM TASK 78-36-00-010-806).

4. Procedure
Subtask 78-37-00-040-056-A

A. Deactivation of the Electrical Tertiary Lock System
(1) Push and hold the tertiary lock system lever (2) in the direction of the tertiary lock system (1). This puts the lever (2) in the retracted position which permits the lever (2) to turn.
(2) Turn the lever (2) to the UNLOCKED position.
(3) Release the lever (2). A spring in the tertiary lock system (1) will move the lever (2) back to the extended position.
(4) Do a check to make sure that the lever (2) aligns with the UNLOCKED position written on the tertiary lock system (1). Do not let the lever (2) stay in a position between UNLOCKED and ACTIVE.

5. Close-up
Subtask 78-37-00-410-054-A

A. Close Access
(1) The following steps are applicable only if the TLS inhibition is related to MMEL purpose:
(a) Make sure that the work area is clean and clear of tools and other items.
(b) Do the reactivation of the Thrust Reverser system for maintenance (Ref. AMM TASK 78-30-00-040-807).
(c) Close the thrust reverser 6 o'clock aft access door (Ref. AMM TASK 78-36-00-410-806).
(d) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-803):
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR
3 Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:37:22 UTC