DOCUMENT NUMBER:
L500-912.820 ISSUE JUL 20, 2016
AMENDMENT: 00
DATE: 
CHAPTERPAGE 355
MAINTENANCE MANUAL STEMME S12
3.7.18.4 TRANSFER PUMP CONTROL AND TANK SELECTION
The transfer pumps are powered by the engine electrical system. They transfer pumps are con-
trolled by a oat switch in the feeder tank and by a pump selector switch. At feeder tank fuel levels
below 90% the transfer pump control is active. The pilot selects the pump on a rotary switch with
the positions LEFT-BOTH-RIGHT. Due to the check valves downstream from the transfer pumps,
the related tank outlet will be closed o completely when the associated transfer pump is not
powered. Thus the pump selector switch functions as a tank selector.
The selected transfer pump/pumps stops automatically when the fuel level reaches 90% in the
feeder tank. On feeder tank-fuel level below 90% the selected transfer pump/pumps start auto-
matically.
The transfer pumps can be activated manually by a test push-button in the cockpit center console
when the Master Switch is ON. This function is used for daily inspection or Maintenance Tasks.
The transfer pump/pumps to be tested can be selected by using the fuel selector switch (Left,
Right, Both).
3.7.19 FUEL QUANTITY INDICATION ATA 284000
3.7.19.1 DESCRIPTION
A oat type fuel level sender is installed in each fuel tank in the wing. The electrical resistance of
the sender changes depending on the oat position. This resistance is measured and displayed
to the pilot on one pointer-type fuel level indicator for each tank. The indicator scale is marked
with lines, each representing one eighth of full.
A separate oat type switch is installed in the feeder tank which activates a yellow low fuel warn-
ing light on the instrument panel at feeder tank fuel levels below ca. 2.5 ltr.
The fuses for the fuel level indicator system are located in the instrument panel fuse holder (en-
gine bus).
3.7.19.2 PARTS SPECIFICATION
Part STEMME p/n Manufacturer p/n
Fuel Quantity Indicator 831.435 UMA T18112F1F4, TSO
Fuel Level Sender 851.503 VDO 226 801 015 001 G, modied
3.7.19.3 OPERATION
The fuel quantity indication system does not require any operation actions by the pilot.
Instructions to the pilot in case of low fuel level situation can be found in the AFM.
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