THRUSH AIRCRAFT INC – MODEL S2R R1340
AIRCRAFT MAINTENANCE MANUAL
5-6
Effective: 01/01/08
recalibration, carefully check out the fuel
quantity indicating electrical system
before deciding that recalibration is
necessary.
A. The fuel quantity indicating system is
calibrated as follows:
B. Defuel aircraft as outlined in Section
2.
C. Level aircraft as outlined in Section 2.
D. Remove the inboard fuel tank access
cover on both wings.
E. Ensure that wing tanks are both
empty. Slowly add 2 gallons of fuel
to each wing tank.
F. Back the plug on top of the header
tank out (do not remove) to allow air
to escape. Tighten the plug when
fuel comes out around it.
G. Slowly add additional fuel to each
wing tank until the forward fuel outlet
ports are just covered with fuel (rear
outlet ports will be covered first). If
one wing tank reaches this condition
before the other, level the airplane
laterally so that forward outlet ports
in both wings are barely covered at
the same time.
*NOTE*
Because both tanks feed the
header tank, fuel will cross-
feed when there are different
amounts of fuel in the two
wings. Therefore, give the
tanks some time to equalize
after fueling the second tank.
H. Connect an APU (auxiliary power
unit) to the external power
connector.
I. Turn APU on and adjust to 27.5 volts.
J. Turn battery switch ON. Readjust
APU to 27.5 volts, if necessary.
K. Place fuel quantity selector switch to
L.H. fuel tank.
L. With the transmitter float free to float
on the unusable fuel in the tank,
center the indicator needle on the “0”
mark by adjusting the trimmer screw
on back of the indicator.
M.
Switch the fuel quantity selector
switch to the R.H. fuel tank and
repeat procedure K for the right hand
tank.
N. If the left and right “0” indications are
different, adjust the indicator to the
lowest one.
O. Replace the inboard fuel tank access
cover on both wings.
P. Fill both fuel tanks with 15 gallons of
fuel. Ascertain that the fuel quantity
indicator for both tanks reads within -
2 to +3 gallons of the center of the
“15” mark. For reference, the width
of the “15” mark represents
approximately 3 gallons.
Q. Fill both fuel tanks with an additional
15 gallons of fuel. Ascertain that the
fuel quantity indicator for both tanks
reads within -2 to +3 gallons of the
center of the “30” mark.
R. Repeat step R. for the “45” and “59”
gallon marks. Ref. Table 5-1.
S. Turn off and disconnect the APU.
T. Turn battery switch OFF.
U. Watch the fuel tanks, hoses and
header tank for a while to be sure
there are no fuel leaks.
TABLE 5-1: TANK CONTENTS VS. REQUIRED INDICATOR READING
FUEL IN
TANK
Unusable 15 Gallons 30 Gallons
45 gallons
59 gallons
Greater than
59 gallons
INDICATOR
READING
0
15 (-3, +5)
30 (-3, +5)
45 (-3, +5)
59 (-3, +5)
59 (-3, +5)
