Removal of the Center Tank Harness

TASK 28-42-44-000-002-A
Removal of the Center Tank Harness

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

FIN: 18QT

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 4M (13 FT)
No specific	AR	SAFETY BARRIER(S)
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	STRING - DRAW
No specific	AR	TAPE - ADHESIVE
No specific	AR	WARNING NOTICE(S)

B. Referenced Information

REFERENCE	DESIGNATION
TASK 28-10-00-910-001-A	Safety Procedures When You Do Work in a Fuel Tank
TASK 28-10-00-910-002-A	Access to the Fuel Tanks and the Work Areas
TASK 28-25-00-650-001-A	Pressure Defuel
TASK 28-25-00-650-003-A	To Drain Remaining Fuel from the Wing Tanks and the Center Tank
TASK 28-25-00-650-003-A-01	To Drain Remaining Fuel from the Wing Tanks and the Center Tank
TASK 28-42-15-000-002-A	Removal of the Center Tank Fuel-Quantity-Probe
TASK 28-42-15-000-004-A	Removal of the Center (Transfer) Tank Fuel-Quantity Probes
TASK 28-42-47-000-001-A	Removal of the Ultracomp
TASK 28-46-15-000-004-A	Removal of the Center-Tank Fuel-Level Sensors
TASK 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 57-17-11-000-001-A	Removal of Access Cover 147AZ(148AZ)
TASK 57-17-11-000-001-B	Removal of Access Cover 148AZ or/and the ACT-Equipment Support Door
Center Tank Harness 18QT - Location and Detail ** ON A/C NOT FOR ALL
Center Tank Harness 18QT - Location and Detail ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 28-42-44-941-054-A

A. Safety Precautions

WARNING: BEFORE YOU DO WORK IN OR NEAR A FUEL TANK, MAKE SURE THAT YOU OBEY ALL THE SAFETY PROCEDURES. THIS WILL PREVENT INJURY TO PERSONS AND/OR DAMAGE TO THE AIRCRAFT.

(1) You must obey the fuel safety procedures (Ref. AMM TASK 28-10-00-910-001) when you do work in a fuel tank.
(2) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(3) Put a WARNING NOTICE(S) in position to tell persons not to operate the MLG doors.

Subtask 28-42-44-865-054-A

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FUEL/FQI/CHAN/1	1QT	A13
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L26
** ON A/C ALL
121VU	FUEL/FQI/CHAN/2	2QT	M27
** ON A/C NOT FOR ALL
121VU	FUEL/CTR TK/AUTO/CTL	3QL	R27
121VU	FUEL/CTR TK/L&R XFR/CTL & IND	2QL	R26
121VU	FUEL/CTR TK/L&R XFR/CTL & IND	1QL	R25
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L25

Subtask 28-42-44-650-055-A

C. Fuel Configuration
(1) Defuel the aircraft (Ref. AMM TASK 28-25-00-650-001).
(2) Make sure that the remaining fuel has been drained from the aircraft (Ref. AMM TASK 28-25-00-650-003).

Subtask 28-42-44-010-053-A

D. Get Access
(1) Open the applicable MLG doors (Ref. AMM TASK 32-12-00-010-001).
(2) Make sure that the 460005835 SLEEVE - GROUND LOCK is on the applicable MLG door actuating-cylinder.
(3) Put the ACCESS PLATFORM 4M (13 FT) below the applicable cover 147AZ(148AZ).
(4) Remove the applicable access panels 147AZ(148AZ) (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-17-11-000-001).

4. Procedure
Subtask 28-42-44-020-052-C ** ON A/C NOT FOR ALL

A. Removal of the Harness

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(1) Disconnect the center tank harness 18QT:
(a) Disconnect the center tank harness from the probes 35QT and 51QT (Ref. AMM TASK 28-42-15-000-004).
(b) Disconnect the center tank harness from the sensor 22QJ (Ref. AMM TASK 28-46-15-000-004).
(c) Disconnect the center tank harness from the ultracomp 50QT (Ref. AMM TASK 28-42-47-000-001).
(2) Attach together all the connectors at all ends of the harness with TAPE - ADHESIVE.

NOTE: This will help the harness to move through its conduit.

(3) Disconnect the center tank harness from the aircraft structure:
(a) Remove the screws (1) and (2), and the washers (3) from the loop clamps (4), (5), (6), (7), (8) and (9).
(b) Remove the screw (10) and the nut (11) from the loop clamps (13) and (14).
(c) Release the harness (23) from the loop-clamps (5), (6), (9) and (14).
(4) If necessary, temporarily install the items that follow:

the harness (22)
the loop-clamps (4), (5), (6), (7), (8), (9) and (14)
the screws (1), (2) and (10)
the washers (3)
the nuts (11).

(5) Attach STRING - DRAW to the longest end of the harness (23).

NOTE: This will help you to install a new center tank harness.

(6) Remove the electrical connector (20) from the applicable electrical backshell (21).
(7) Remove and discard the the lockwire from the nut (19).
(8) Remove the nut (19) and the washer (18).
(9) Remove the electrical backshell (21) and the O-ring (17) from the tank wall.
(10) Make sure that the center tank harness (23) is free to move through its conduit (15).
(11) Carefully pull the electrical backshell (21) to remove the center tank harness from the aircraft. When you remove the center tank harness make sure that it does not catch.
(12) Remove the center tank harness from the string. Make sure that you do not pull the string out of the conduit (15).

Subtask 28-42-44-020-052-D ** ON A/C NOT FOR ALL

A. Removal of the Harness

(1) Disconnect the center tank harness 18QT:
(a) Disconnect the center tank harness from the probes 35QT and 39QT (Ref. AMM TASK 28-42-15-000-002):
(b) Disconnect the center tank harness from the sensor 22QJ (Ref. AMM TASK 28-46-15-000-004).
(2) Attach together all the connectors at all ends of the harness with TAPE - ADHESIVE.

NOTE: This will help the harness to move through its conduit.

the harness (22)
the loop-clamps (4), (5), (7), (8), (9) and (14)
the screws (1), (2) and (10)
the washers (3)
the nuts (11).

(5) Attach STRING - DRAW to the longest end of the harness (23).

NOTE: This will help you to install a new center tank harness.

(6) Disconnect the electrical connector (20) from the applicable fused adapter (24).
(7) Remove the fused adapter (24) from the electrical backshell (21).
(8) Remove and discard the lockwire from the nut (19).
(9) Remove the nut (19) and the washer (18).
(10) Remove the electrical backshell (21) and the O-ring (17) from the tank wall.
(11) Make sure that the center tank harness (23) is free to move through its conduit (15).
(12) Carefully pull the electrical backshell (21) to remove the center tank harness from the aircraft. When you remove the center tank harness make sure that it does not catch.
(13) Remove the center tank harness from the string. Make sure that you do not pull the string out of the conduit (15).

[Rev.10 from 2021] 2026.04.02 06:18:11 UTC