Level Sensing Test - ACT

TASK 28-46-00-740-002-A
Level Sensing Test - ACT

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.

1. Reason for the Job
The FLSCU3 (47QJ) and related fuel level sensors are not Automatic FLSS BITE tested or monitored by the FQIC (3QT).
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	MULTIMETER - STANDARD
No specific	AR	SAFETY BARRIER(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
192MB, 811

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-11-28-650-003-A	Pressure Refuel with Automatic Control
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 28-25-00-869-001-A	Fuel Transfer
TASK 28-46-00-740-001-A	Functional (BITE) Test
TASK 28-46-34-000-001-B	Removal of the Fuel-Level Sensing Control-Unit (FLSCU)
TASK 28-46-34-400-001-B	Installation of the Fuel-Level Sensing Control-Unit (FLSCU)
TASK 31-60-00-860-002-A	EIS Stop Procedure

3. Job Set-up
Subtask 28-46-00-941-057-A ** ON A/C NOT FOR ALL

A. Safety Precautions

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

(1) You must obey the fuel safety procedures when you do work on the fuel system (Ref. AMM TASK 28-00-00-910-001).
(2) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.

Subtask 28-46-00-010-056-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at the access door 811 in zone 122.
(2) Open the access doors 811 and 192MB.

Subtask 28-46-00-860-057-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration

WARNING: MAKE SURE THAT ALL THE CIRCUITS IN MAINTENANCE ARE ISOLATED BEFORE YOU SUPPLY ELECTRICAL POWER TO THE AIRCRAFT. UNWANTED ELECTRICAL POWER CAN BE DANGEROUS.

(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) If the external power is not available, on the refuel/defuel panel 800VU:

put the BATT POWER switch to the ON position.

NOTE: HOT BUSS 701PP is energized for ten minutes only to prevent discharge of the aircraft batteries, unless you put the MODE SELECT switch to REFUEL.

Subtask 28-46-00-865-056-A ** ON A/C NOT FOR ALL

D. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	FUEL/FQI/CHAN/1	1QT	A13
49VU	FUEL/AFT LOW LVL/& OVFL/WING R	44QJ	A11
49VU	FUEL/AFT LOW LVL/& OVFL/WING L	43QJ	A10
121VU	ACT1/REFUEL & SPLY	33QU	L29
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L26
121VU	FUEL/HI/LVL/SPLY	1QJ	L25
121VU	FUEL/RFL/DFL/SPLY	2QU	L24
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L23
121VU	ACT LOW LVL R	51QJ	M29
121VU	ACT LOW LVL L	52QJ	M28
121VU	FUEL/FQI/CHAN/2	2QT	M27
121VU	FUEL/FWD LOW LVL/WING/R	45QJ	M23
121VU	FUEL/FWD LOW LVL/WING/L	46QJ	M22
121VU	ACT XFR VALVE MAN CTL	30QH	N29
121VU	ACT1/CTL & SPLY	9QH	P29
121VU	ACT PUMP SUPPLY	25QH	Q29
121VU	FUEL/CTR TK/L&R XFR/CTL & IND	2QL	R26
121VU	FUEL/CTR TK/L&R XFR/CTL & IND	1QL	R25

4. Procedure
Subtask 28-46-00-740-052-A ** ON A/C NOT FOR ALL

A. Test of the FLSCU3 with BITE
(1) Do the BITE test of the FLSCU1 (7QJ) and the FLSCU2 (9QJ) (Ref. AMM TASK 28-46-00-740-001). Make sure that the test result is good.

NOTE: The FLSS BITE test is only done on the FLSCUs installed in the FLSCU1 and the FLSCU2 positions. There is no FLSS BITE test function done to the FLSCU installed in the FLSCU3 position.

(2) Remove and retain the FLSCU1 (Ref. AMM TASK 28-46-34-000-001).
(3) Remove the FLSCU3 (Ref. AMM TASK 28-46-34-000-001).
(4) Install the FLSCU initially installed in the FLSCU3 position in the FLSCU1 position (Ref. AMM TASK 28-46-34-400-001).
(5) Do the BITE test (Ref. AMM TASK 28-46-00-740-001). Make sure that the test result is good.
(6) Remove the FLSCU3 from the FLSCU1 position (Ref. AMM TASK 28-46-34-000-001).
(7) Install the FLSCU1 and the FLSCU3 in their initial positions (Ref. AMM TASK 28-46-34-400-001).

Subtask 28-46-00-740-055-A ** ON A/C NOT FOR ALL

B. Manual Test of the High Level Sensors of 65QT1(65QT2) and 66QT1(66QT2)
(1) Do this test:

ACTION	RESULT
On the panel 800VU: put the TEST switch to the LTS position and hold it there	On the panel 800VU and 801VU: the HI LVL lights and the DEFUEL XFR OPEN light are on.
	On the preselector 5QT: the PRESELECTED and ACTUAL displays show all eights the CKPT and END lights come on.
	On the indicator 6QT: the FUEL QTY displays show all eights.
release the TEST switch	On the panel 800VU and 801VU: the HI LVL lights and the DEFUEL XFR OPEN light go back to their initial condition. NOTE: If the ACT1 contains more than approximately 2349 kg (5179 lb), the ACT1 HI LVL light will be on. If the ACT2 is installed and contains more than approximately 2349 kg (5179 lb), the ACT2 HI LVL light will be on. This is a full indication as the high level sensors are wet.
	On the preselector 5QT: the CKPT and END lights go off the PRESELECTED and ACTUAL displays show the tank quantities.
	On the indicator 6QT: the FUEL QTY displays show the tank quantities. NOTE: The correct indication of high level sensor states may not show for 60 seconds after you switch the power on. This can occur at extreme conditions of temperature and battery voltage.
put the TEST switch to the HI LVL position and hold it there	On the panel 800VU and 801VU: make sure all the HI LVL lights change from their initial condition. Any HI LVL lights that were on are now off. Any HI LVL lights that were off are now on.
release the TEST switch.	On the panel 800VU and 801VU: make sure all the HI LVL lights go back to their initial condition.

Subtask 28-46-00-710-056-A ** ON A/C NOT FOR ALL

C. Functional Test of the Low Level Sensors of 65QT1 and 66QT1
(1) Make sure that the ACT1 contains more than 250 kg (551 lb) of fuel. Refuel the ACT1 if necessary (Ref. AMM TASK 12-11-28-650-003).

NOTE: This is to make sure that the low level sensors are wet.

(2) Disconnect the free connector 4065VC-A from the Relay Panel (802VU).
(3) With a MULTIMETER - STANDARD at the free connector 4065VC-A, do a resistance test between the pins <A and <B and a resistance test between pin <D and a ground point. The result must be open circuit for both tests.

NOTE: The tests are related to the low level sensors as follows:

between pin <D and ground is for 65QT1 (FLSCU3 channel LS1)
between pins <A and <B is for 66QT1 (FLSCU3 channel LS5).

(4) Defuel the ACT1 (Ref. AMM TASK 28-25-00-869-001).

NOTE: This is to make sure that the low level sensors are dry.

(5) With a multimeter at the free connector 4065VC-A, do a resistance test between the pins <A and <B and a resistance test between pin <D and a ground point. The result must be a low resistance for both tests.
(6) Connect the free connector 4065VC-A to the Relay Panel (802VU).

Subtask 28-46-00-710-061-A ** ON A/C NOT FOR ALL

D. Functional Test of the Low Level Sensors of 65QT2 and 66QT2
(1) Make sure that the ACT2 contains more than 250 kg (551 lb) of fuel. Refuel the ACT2 if necessary (Ref. AMM TASK 12-11-28-650-003).

NOTE: This is to make sure that the low level sensors are wet.

(2) Disconnect the free connector 4065VC-A from the Relay Panel (802VU).
(3) With a MULTIMETER - STANDARD at the free connector 4065VC-A, do a resistance test between these positions:

pins B and D
pin C and a ground point.
The result must be open circuit for both tests.

NOTE: The tests are related to the low level sensors as follows:

between pin C and ground is for 65QT2 (FLSCU3 channel LS8)
between pins B and D is for 66QT2 (FLSCU3 channel LS2).

(4) Defuel the ACT2 (Ref. AMM TASK 28-25-00-869-001).

NOTE: This is to make sure that the low level sensors are dry.

(5) With a MULTIMETER - STANDARD at the free connector 4065VC-A, do a resistance test between these positions:

pins B and D
pin C and a ground point.
The result must be a low resistance for both tests.

(6) Connect the free connector 4065VC-A to the Relay Panel (802VU).

5. Close-up
Subtask 28-46-00-410-055-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 the access doors 811 and 192MB.

Subtask 28-46-00-860-058-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) If the aircraft is refueled with the battery power, on the refuel/defuel control panel (800VU):

put the BATT POWER switch to the NORM position.

(2) If the external power is available, do the steps that follow:
(a) Do the EIS stop procedure
(Ref. AMM TASK 31-60-00-860-002).
(b) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

Subtask 28-46-00-942-057-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.02 06:18:15 UTC