Diamond DA 40 Flight Manual page 262

Airplane
Description
b) Long Range Tank
For ascertaining fuel quantity in the enlarged tanks an additional capacitive probe is used
on each side (LH/RH). When the fuel quantity indicator reads zero, only the unusable
fuel remains in the tank. The usable capacity of each tank is 25 US gal (approximately
94 liter).
Up to an actual fuel quantity of 16 US gal the fuel quantity is measured by the standard
probes and is brought to indication on the left and right side of the instrument in increments
of 1 US gal.
A fuel quantity between 16 US gal and 25 US gal is ascertained by the additional probes
and is brought to indication in the central area of the fuel quantity indicator. The indication
is numerical in 3 US gal steps (in the range from 0 to 3 US gal) and 1 US gal steps (in
the range above 3 US gal up to max. 9 US gal). The side to be indicated can be selected
by the AUX FUEL QTY switch (see figure below) which is located next to the indicator.
The indication on the left and right side of the instrument (0 US gal to max. 16 US gal)
is not affected by the switch.
Page 7 - 36 Rev. 8 01-Dec-2010
DA 40 AFM
Doc. # 6.01.01-E