Installation of the Center Tank Harness

TASK 28-42-44-400-001-A
Installation of the Center Tank Harness

WARNING: MAKE SURE THAT THE FLIGHT CONTROL SAFETY-LOCKS AND THE WARNING NOTICES ARE IN POSITION.

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.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

FIN: 17QT

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	SPATULA - PLASTIC
No specific	AR	TAPE - ADHESIVE
No specific	Torque wrench: range to between 1.07 and 0.96 m.daN (94.69 and 84.96 lbf.in )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.06ABA1)	Polysulfide Sealant-Fuel Tank Brushable -
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
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 28-42-00-740-001-A	Status Report (BITE)
TASK 28-42-15-400-002-A	Installation of the Center Tank Fuel-Quantity-Probe
TASK 28-42-15-400-004-A	Installation of the Center (Transfer) Tank Fuel-Quantity Probe
TASK 28-42-16-400-002-A	Installation of the Cadensicon
TASK 28-42-47-400-001-A	Installation of the Ultracomp
TASK 28-46-00-740-001-A	Functional (BITE) Test
TASK 28-46-15-400-012-A	Installation of the Center-Tank Fuel-Level Sensors
TASK 32-12-00-410-001-A	Close the Main Gear Doors after 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
TASK 57-17-11-400-001-A	Installation of Access Cover 147AZ(148AZ)
TASK 57-17-11-400-001-B	Installation of Access Cover 148AZ or/and the ACT-Equipment Support-Door
Center Tank Harness 17QT - Location and Detail ** ON A/C NOT FOR ALL
Center Tank Harness 17QT - Location and Detail ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 28-42-44-941-052-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) Make sure that the SAFETY BARRIER(S) are in position.

Subtask 28-42-44-860-050-A

B. Aircraft Maintenance Configuration
(1) Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

1QL, 2QL, 3QL, 1QT, 2QT and 8QT.

(2) Make sure that the applicable fuel tank is defueled (Ref. AMM TASK 28-25-00-650-001) .
(3) Make sure that the ACCESS PLATFORM 4M (13 FT) is below the applicable cover 147AZ(148AZ).
(4) Make sure that the applicable access cover 147AZ(148AZ) has been removed (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-17-11-000-001).

4. Procedure

WARNING: MAKE SURE THAT ALL CABLES IN FUEL TANKS ARE CORRECTLY SUPPORTED (BY CLIPS AND OTHER SUPPORTS). IF CLIPS OR SUPPORTS ARE MISSING OR DAMAGED, YOU MUST REPLACE THEM.

WARNING: DO NOT REPAIR CABLES THAT ARE IN FUEL TANKS. DO NOT MAKE IN-LINE SPLICES. IF A CABLE IS DEFECTIVE, YOU MUST REPLACE THE FULL CABLE ASSEMBLY.

WARNING: MAKE SURE THAT THE INSTALLATION AND ROUTING OF ALL ELECTRICAL CABLES AGREE WITH THE REQUIREMENTS OF THE ELECTRICAL STANDARD PRACTICES MANUAL.

Subtask 28-42-44-420-052-A

A. Preparation for Installation

WARNING: WHEN YOU USE COMPRESSED AIR:

USE THE CORRECT PROTECTION (FACE SHIELD OR GOGGLES)
DO NOT POINT THE AIRFLOW AT YOURSELF OR OTHER PERSONS.

LOOSE PARTICLES AND/OR HIGH PRESSURE AIR CAN CAUSE INJURY.

WARNING: DO NOT LET COMPRESSED GAS TOUCH YOUR SKIN. THE GAS CAN GO THROUGH THE SKIN AND MAKE BUBBLES IN THE BLOOD. THIS CONDITION CAN KILL YOU.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

(1) Use a SPATULA - PLASTIC to remove the sealant at the interface of the electrical backshell (21) and the tank wall.
(2) Use a Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) to clean:

the electrical backshell (21)
the interface of the electrical backshell (21) and the tank wall.

(3) Dry the cleaned areas with compressed air.
(4) Make sure the parts retained from the removed component are clean and in the correct condition.

Subtask 28-42-44-420-050-C ** ON A/C NOT FOR ALL

B. Installation 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.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

(1) Use TAPE - ADHESIVE to secure the electrical connectors of the new harness (22) together. Attach the string to the end of the harness.

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

(2) Use the string to pull the center tank harness (22) through its conduit (16). When you install the center tank harness make sure it does not catch.
(3) Remove and discard the adhesive tape and the string from the harness (22).
(4) Put the harness (22) in position.
(5) If necessary remove the items that follow:

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

(6) Put the loop-clamps (4), (5), (7), (8) and (9) with the harness (22) in position. Align loop clamp (14) with probe clamps (12) and (13).
(7) If necessary put the loop-clamps (5), (6) and (9) with the harness (23) in position.
(8) Install the screws (1), (2) and (10) with washers (3) and the nuts (11) and tighten.
(9) Make sure that the electrical connectors are clean and in the correct condition.
(10) Connect the center tank harness 17QT:
(a) Identify the cable ends for the probes 36QT, 37QT and 38QT and connect them to the correct terminals (Ref. AMM TASK 28-42-15-400-004).
(b) Identify the cable ends for the sensors 20QJ and 21QJ and connect them to the correct terminals (Ref. AMM TASK 28-46-15-400-012).
(c) Identify the cable ends for the ultracomp 50QT and connect them to the correct terminals (Ref. AMM TASK 28-42-47-400-001).
(11) Install the O-ring (17) on the electrical backshell (21).
(12) Install the electrical backshell (21) in the applicable position.
(13) Install the washer (18) and the nut (19).
(14) TORQUE the nut (19) to between 1.07 and 0.96 m.daN (94.69 and 84.96 lbf.in )

.
(15) Safety the nut (19) to the nut on the adjacent electrical backshell with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(16) Apply Polysulfide Sealant-Fuel Tank Brushable - (Material No.06ABA1) around the electrical backshell (21) to seal it to the tank wall.
(17) Connect the electrical connector (20) to the electrical backshell (21).
(18) Do a bonding check between the electrical connector (20) and FR42 (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10milliohms.

Subtask 28-42-44-420-050-D ** ON A/C NOT FOR ALL

B. Installation of the Harness

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

(1) Use TAPE - ADHESIVE to secure the electrical connectors of the new harness (22) together. Attach the string to the end of the harness.

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

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

(6) Put the loop-clamps (4), (5), (7), (8) and (9) with the harness (22) in position. Align loop clamp (14) with probe clamps (12) and (13).
(7) If necessary put the loop-clamps (5), (6) and (9) with the harness (23) in position.
(8) Install the screws (1), (2) and (10) with washers (3) and the nuts (11) and tighten.
(9) Make sure that the electrical connectors are clean and in the correct condition.
(10) Connect the center tank harness 17QT:
(a) Identify the cable ends for the probes 36QT, 37QT and 38QT and connect them to the correct terminals (Ref. AMM TASK 28-42-15-400-002).
(b) Identify the cable ends for the sensors 20QJ and 21QJ and connect them to the correct terminals (Ref. AMM TASK 28-46-15-400-012).
(c) Identify the cable ends for the cadensicon 20QT and connect them to the correct terminals (Ref. AMM TASK 28-42-16-400-002).
(11) Install the O-ring (17) on the electrical backshell (21).
(12) Install the electrical backshell (21) in the applicable position.
(13) Install the washer (18) and the nut (19).
(14) TORQUE the nut (19) to between 1.07 and 0.96 m.daN (94.69 and 84.96 lbf.in )

.
(15) Safety the nut (19) to the nut on the adjacent electrical backshell with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(16) Apply Polysulfide Sealant-Fuel Tank Brushable - (Material No.06ABA1) around the electrical backshell (21) to seal it to the tank wall.
(17) Connect the fused adapter (24) to the electrical backshell (21).
(18) Connect the electrical connector (20) to the fused adapter (24).
(19) Do a bonding check between the electrical connector (20) and FR42 (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.

Subtask 28-42-44-865-051-A

C. Remove the safety clip(s) and the tag(s) and close 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 28-42-44-410-052-A

D. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the applicable cover(s) 147AZ(148AZ) (Ref. AMM TASK 57-17-11-400-001).
(3) Close the MLG doors (Ref. AMM TASK 32-12-00-410-001).

Subtask 28-42-44-740-052-A

E. Test
(1) Do a status report (BITE) of the fuel-quantity indicating system (Ref. AMM TASK 28-42-00-740-001).
(2) Do a functional (BITE) test of the fuel-tank level-sensing system (Ref. AMM TASK 28-46-00-740-001).

5. Close-up
Subtask 28-42-44-942-053-A

A. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

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