Installation of the Auxiliary Level Sensing Control-Unit (ALSCU)

TASK 28-46-35-400-001-A
Installation of the Auxiliary Level Sensing Control-Unit (ALSCU)

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

ZONE: 120
FIN: 60QJ ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
120	AVIONICS COMPARTMENT
811

B. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
TASK 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
Auxiliary Level Sensing Control-Unit (ALSCU)

3. Job Set-up
Subtask 28-46-35-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Obey the fuel safety procedures (Ref. AMM TASK 28-00-00-910-001).
(2) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(3) Make sure that the WARNING NOTICE(S) are in position on the panels that follow, to tell persons not to operate the fuel system:

Refuel/Defuel panels 800VU and 801VU
Fuel control panel 40VU
Additional Center Tank (ACT) control panel 28VU.

(4) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position below access door 811.
(5) Make sure that access door 811 is open (Ref. AMM TASK 52-41-00-010-002).

Subtask 28-46-35-865-051-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ALSCU SPLY	66QJ	B10
121VU	FUEL/ALSCU/HI LEVEL/SPLY	64QJ	K21
121VU	FUEL/ALSCU/SPLY	65QJ	K20

4. Procedure
Subtask 28-46-35-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the ALSCU

Auxiliary Level Sensing Control-Unit (ALSCU) ** ON A/C NOT FOR ALL

(1) Do an inspection of the component interfaces and the adjacent area.
(2) Clean the component interfaces and the adjacent area.

CAUTION: DO NOT TOUCH THE CONNECTOR PINS OR OTHER CONDUCTORS ON THE COMPONENT DURING THE PROCEDURE. IF YOU TOUCH THESE CONDUCTORS, ELECTROSTATIC DISCHARGE CAN CAUSE DAMAGE TO COMPONENT.

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

(3) Remove the CAP-BLANKING from each electrical connector and receptacle.
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Put the ALSCU (1) on its rack (2).
(6) Carefully push the ALSCU (1) on the rack (2) to connect it to the electrical connector (3).
(7) Attach the ALSCU (1) to its rack (2) with the knurled nut (4).

Subtask 28-46-35-865-052-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ALSCU SPLY	66QJ	B10
121VU	FUEL/ALSCU/HI LEVEL/SPLY	64QJ	K21
121VU	FUEL/ALSCU/SPLY	65QJ	K20

5. Close-up
Subtask 28-46-35-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close access door 811 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).

Subtask 28-46-35-862-050-A ** ON A/C NOT FOR ALL

B. Put the aircraft back to its initial configuration.
(1) Remove the warning notices from the panels that follow:

Refuel/Defuel control panels 800VU and 801VU.
Fuel control panel 40VU
ACT control panel 28VU.

(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.02 06:18:17 UTC