Test of the Tank High-Level Sensing-System

TASK 28-46-00-710-001-A
Test of the Tank High-Level Sensing-System

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
To test at the refuel/defuel panel 800VU the:

HI LVL lights (lamp check)
high level sensors in the fuel tanks
FLSCU 7QJ(9QJ) (high level channels).

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 3M (10 FT)
No specific	AR	SAFETY BARRIER(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
622KB
192MB

C. 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 31-60-00-860-002-A	EIS Stop Procedure

3. Job Set-up
Subtask 28-46-00-941-054-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 28-46-00-010-052-D ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the access door 192MB to energize the refuel/defuel control panel.

NOTE: If operating in battery power:

put the MODE SELECT switch to the OFF and guarded position
do not keep the door open longer than necessary because the battery can discharge.

Subtask 28-46-00-010-052-E ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT) below zone 622.
(2) Open the access door 622KB to energize the refuel/defuel control panel.

NOTE: If operating in battery power:

put the MODE SELECT switch to the OFF and guarded position
do not keep the door open longer than necessary because the battery can discharge.

Subtask 28-46-00-860-054-B ** 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.

4. Procedure
Subtask 28-46-00-710-053-A ** ON A/C NOT FOR ALL

A. Test of the HI LVL Lights
(1) Do the steps given below:

ACTION	RESULT
1.On the panel 800VU:	On the panel 800VU:
set the REFUEL VALVES switches to the NORM and guarded position set the MODE SELECT switch to the OFF position.
hold the TEST switch in the LTS position.	if the HI LVL lights were off they come on if the HI LVL lights were on they stay on.
- release the TEST switch.	if the HI LVL lights came on they go off if the HI LVL lights were on they stay on.

Subtask 28-46-00-710-054-A ** ON A/C NOT FOR ALL

B. High-Level Sensing-System Test

NOTE: The subsequent results of the high level test must agree with the quantity of fuel in each tank. You must do a check (for each tank) on the multi-tank indicator to find which of these conditions is applicable:

condition 1: The quantity of fuel is less than the high level
condition 2: The quantity of fuel is at, or more than, the high level.

(1) Do this test:

ACTION	RESULT
1.On the panel 800VU:	On the panel 800VU:
hold the TEST switch in the HI LVL position.	For condition 1 (see note): the HI LVL light for each applicable tank comes on.
	For condition 2 (see note): the HI LVL light for each applicable tank goes off.
release the TEST switch.	For condition 1 (see note): the HI LVL light for each applicable tank goes off.
	For condition 2 (see note): the HI LVL light for each applicable tank comes on.

Subtask 28-46-00-710-053-B ** ON A/C NOT FOR ALL

C. Test of the HI LVL Lights
(1) Do the steps given below:

ACTION	RESULT
1.On panels 800VU and 801VU:
Set the REFUEL VALVES switches to the NORM and guarded position Set the MODE SELECT switch to the OFF position.
2.On panel 800VU:	On panels 800VU and 801VU:
Hold the TEST switch in the LTS position.	If the HI LVL lights were off they come on If the HI LVL lights were on they stay on.
- Release the TEST switch.	If the HI LVL lights came on they go off If the HI LVL lights were on they stay on.

Subtask 28-46-00-710-054-B ** ON A/C NOT FOR ALL

D. High-Level Sensing-System Test

Condition 1: The quantity of fuel is less than the high level
Condition 2: The quantity of fuel is at, or more than, the high level.

(1) Do this test:

ACTION	RESULT
1.On panel 800VU:	On panels 800VU and 801VU:
Hold the TEST switch in the HI LVL position	For condition 1 (see note): The HI LVL light for each applicable tank comes on.
	For condition 2 (see note): The HI LVL light for each applicable tank goes off.
Release the TEST switch.	For condition 1 (see note): The HI LVL light for each applicable tank goes off.
	For condition 2 (see note): The HI LVL light for each applicable tank comes on.

5. Close-up
Subtask 28-46-00-860-055-B ** ON A/C NOT FOR ALL

A. 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 28-46-00-410-052-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 192MB.

Subtask 28-46-00-410-052-B ** ON A/C NOT FOR ALL

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 622KB.

Subtask 28-46-00-942-055-A ** ON A/C NOT FOR ALL

C. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the access platform(s).
(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