LEFT HI LVL Manual TEST

TASK 28-46-00-810-823-A
LEFT HI LVL Manual TEST

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

1. Possible Causes

FLSCU-1 [7QJ]
FLSCU-2 [9QJ]
CTL PNL-REFUEL/DEFUEL [800VU]
aircraft wiring
HARNESS-CHAN A, L WING TK INR [13QT1]
SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1]
SW-TEST/LTS/HIGH [2QJ]
HARNESS-LEFT WING TANK A [57QT]

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

REFERENCE	QTY	DESIGNATION
No specific	AR	MULTIMETER - STANDARD

B. Referenced Information

REFERENCE	DESIGNATION
AMM 28-10-00-910-001	Safety Procedures When You Do Work in a Fuel Tank
AMM 28-25-55-000-001	Removal of the Refuel Panel
AMM 28-25-55-400-001	Installation of the Refuel Panel
AMM 28-42-43-000-005	Removal of the Wing Tank Harness
AMM 28-42-43-000-006	Removal of the Wing-Tank Inner-Cell Group A Harness
AMM 28-42-43-400-005	Installation of the Wing Tank Harness
AMM 28-42-43-400-006	Installation of the Wing-Tank Inner-Cell Group A Harness
AMM 28-46-00-710-001	Test of the Tank High-Level Sensing-System
AWM 284601
AWM 284602
AMM 28-46-15-000-001	Removal of the Wing-Tank Fuel-Level Sensors
AMM 28-46-15-400-009	Installation of the Wing-Tank Fuel-Level Sensors
AMM 28-46-34-000-001	Removal of the Fuel-Level Sensing Control-Unit (FLSCU)
AMM 28-46-34-400-001	Installation of the Fuel-Level Sensing Control-Unit (FLSCU)

3. Fault Confirmation
Subtask 28-46-00-710-054-A ** ON A/C NOT FOR ALL

A. Do the Operational Test of the HI LVL Lights AMM 28-46-00-710-001.

NOTE: You can get more Trouble-shooting data from the CFDS(FUEL):

Input Parameters Page 3 (Ref. P. Block 301), used with the Fuel Level Sensors Operating (Changeover) Values (Ref. P. Block 301)
FLSCU Trouble-shooting Data (Ref. P. Block 301).

With the HIGH LVL TEST switch in the central (released) position the lamp state, off or on, must agree with the bit indicator 0 or 1 respectively, in the Input Parameters Page 3.

NOTE: OPTIONAL TESTING:
Where a PSD A320-2 Fuel Level Sensing Test Set is available measurements can be taken before a decision is made to go into or close up a fuel tank. The Test Set enables the tank mounted components and tank wiring to be tested from the tank wall connectors.

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

A. Do the Operational Test of the HI LVL Lights AMM 28-46-00-710-001.

NOTE: You can get more Trouble-shooting data from the CFDS(FUEL):

Input Parameters Page 3 (Ref. P. Block 301), used with the Fuel Level Sensors Operating (Changeover) Values (Ref. P. Block 301)
Trouble-shooting Data (Ref. P. Block 301).

With the HIGH LVL TEST switch in the central (released) position the lamp state, off or on, must agree with the bit indicator 0 or 1 respectively, in the Input Parameters Page 3.

NOTE: OPTIONAL TESTING:
Where a PSDA321-1 Test Set is available, a check can be made before a decision is made to go into or close up a fuel tank. The Test Set enables a GO/NOGO check to be made of the tank mounted components and wiring from the tank wall connectors.

4. Fault Isolation
Subtask 28-46-00-810-072-A ** ON A/C NOT FOR ALL

A. If the LEFT HI LVL Indicator light fails to change state, from off to on, or from on to off:

swap the FLSCU-1 [7QJ] with FLSCU-2 (9QJ) AMM 28-46-34-000-001 and AMM 28-46-34-400-001.

(1) Do the test given in Para. 3.A.
(2) If the LEFT HI LVL Indicator light changes state during the test but the fault has transfered to RIGHT HI LVL Indicator light:

replace the FLSCU-2 [9QJ] AMM 28-46-34-000-001 and AMM 28-46-34-400-001.

(3) Do the test given in Para. 3.A.
(4) If the fault continues:
(5) Remove CTL PNL-REFUEL/DEFUEL (800VU) AMM 28-25-55-000-001.
(6) Do a check AWM 284602 with a MULTIMETER - STANDARD of the SW-TEST/HI/LTS (2QJ) between:

connector 4023VC, pin <C, and connector 4024VC, pin R, on the CTL PNL-REFUEL/ DEFUEL (800VU).

The multimeter must show:

open circuit for the switch in the central (released) position
closed circuit for the switch in the TEST position.

NOTE: The LTS test checks the 28VDC supply to the CTL PNL-REFUEL/DEFUEL (800VU).

(7) Replace the CTL PNL-REFUEL/DEFUEL [800VU] , if it fails Step (6) AMM 28-25-55-000-001 and AMM 28-25-55-400-001.

NOTE: If due to airline operational conditions it is not possible to replace the CTL PNL-REFUEL/DEFUEL (800VU) and internal trouble-shooting is required, go to Step (12).

(8) If the fault continues do a check AWM 284601, and AWM 284602 of the aircraft wiring :

between the CTL PNL-REFUEL/DEFUEL (800VU), connector 4024VC, pin R and the FLSCU-1 rack connector AA, pin 13B
between the CTL PNL-REFUEL/DEFUEL (800VU), connector 4024VC, pin T and the FLSCU-1 rack connector AA, pin 7A
between the FLSCU-1 rack connector AA, pin 6A and the DC1 ground/earth point
between the FLSCU-1 rack connector AB, pin 10A and the tank wall connector 4039VC, pin <V
between the FLSCU-1 rack connector AB, pin 10B and the tank wall connector 4039VC, pin EE.

(9) Repair all the unserviceable wiring and connectors.
(10) Do the test given in Para. 3.A.
(11) If the fault continues:
(a) Drain, open and vent the tank AMM 28-10-00-910-001.
(b) Do a check of the HARNESS-CHAN A, L WING TK INR [13QT1] AWM 284602.
(c) If the harness is unserviceable:

replace the harness AMM 28-42-43-000-006 and AMM 28-42-43-400-006.

(d) If the harness is serviceable:

replace the SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1] AMM 28-46-15-000-001 and AMM 28-46-15-400-009.

(12) CTL PNL-REFUEL/DEFUEL internal trouble-shooting AWM 284601 and AWM 284602:
(a) Check/replace the SW-TEST/LTS/HIGH [2QJ] (part of 800VU).
(b) Check/repair the CTL PNL-REFUEL/DEFUEL internal wiring as follows:

connector 4023VC, pin <C to terminal block 4001VT, terminal 5C
terminal block 4001VT, terminal 5J to SW-TEST/HI/LTS (2QJ), terminal 1B
SW-TEST/HI/LTS (2QJ), terminal 3B to connector 4024VC, pin R
connector 4024VC, pin T to IND-HI LVL/LEFT (3QJ), terminal I.

Subtask 28-46-00-810-072-B ** ON A/C NOT FOR ALL

A. If the LEFT HI LVL Indicator light fails to change state, from off to on, or from on to off:

swap the FLSCU-1 [7QJ] with FLSCU-2 (9QJ), AMM 28-46-34-000-001, and AMM 28-46-34-400-001.

(1) Do the test given in Para. 3.A.
(2) If the LEFT HI LVL Indicator light changes state during the test but the fault has transfered to RIGHT HI LVL Indicator light:

replace the FLSCU-2 (9QJ) AMM 28-46-34-000-001 and AMM 28-46-34-400-001.

connector 4023VC, pin <C, and connector 4024VC, pin R, on the CTL PNL-REFUEL/ DEFUEL (800VU).

The multimeter must show:

open circuit for the switch in the central (released) position
closed circuit for the switch in the TEST position.

NOTE: The LTS test checks the 28VDC supply to the CTL PNL-REFUEL/DEFUEL (800VU).

(7) Replace the CTL PNL-REFUEL/DEFUEL [800VU] , if it fails Step (6), AMM 28-25-55-000-001, and AMM 28-25-55-400-001.

NOTE: If due to airline operational conditions it is not possible to replace the CTL PNL-REFUEL/DEFUEL (800VU) and internal touble-shooting is required, go to Step (12).

(8) If the fault continues do a check AWM 284601, and AWM 284602 of the aircraft wiring

between the CTL PNL-REFUEL/DEFUEL (800VU), connector 4024VC, pin R and the FLSCU-1 rack connector AA, pin 13B
between the CTL PNL-REFUEL/DEFUEL (800VU), connector 4024VC, pin T and the FLSCU-1 rack connector AA, pin 7A
between the FLSCU-1 rack connector AA, pin 6A and the DC1 ground/earth point
between the FLSCU-1 rack connector AB, pin 10A and the tank wall connector 4039VC, pin <V
between the FLSCU-1 rack connector AB, pin 10B and the tank wall connector 4039VC, pin EE.

(9) Repair all the unserviceable wiring and connectors.
(10) Do the test given in Para. 3.A.
(11) If the fault continues:
(a) Drain, open and vent the tank AMM 28-10-00-910-001.
(b) Do a check of the HARNESS-LEFT WING TANK A [57QT] AWM 284602.
(c) If the harness is unserviceable:

replace the harness AMM 28-42-43-000-005 and AMM 28-42-43-400-005.

(d) If the harness is serviceable:

replace the SENSOR-HI LEVEL, LEFT WING TANK INNER CHANEL A [17QJ1] AMM 28-46-15-000-001 and AMM 28-46-15-400-009.

connector 4023VC, pin <C to terminal block 4001VT, terminal 5C
terminal block 4001VT, terminal 5J to SW-TEST/HI/LTS (2QJ), terminal 1B
SW-TEST/HI/LTS (2QJ), terminal 3B to connector 4024VC, pin R
connector 4024VC, pin T to IND-HI LVL/LEFT (3QJ), terminal I.

[Rev.8 from Aug 2018] 2026.04.04 04:29:17 UTC