General Description - Thrush Aircraft S2R-R1340 Maintenance Manual

THRUSH AIRCRAFT INC – MODEL S2R R1340
FUEL SYSTEM

GENERAL DESCRIPTION

Ref. Figure 5-1, 5-2 & 5-3
A 133 U.S. gallon useable fuel supply is
available for the Thrush 600.
wing, fuel is contained inside integral
wing tanks (wet wing fuel tanks) just
outboard of the fuselage. The left wing
and right wing
interconnected through a 4.5 U.S. gallon
header tank that is located in the
fuselage. The fuel supply lines to the
engine are routed from the header tank
outlet finger screen through a fuel shutoff
(on/off) valve to an electric powered
auxiliary fuel pump.
pump discharge is then routed through a
25-micron main fuel filter to the engine
driven fuel pump.
pump serves two purposes, first as a
backup system to provide continuous
fuel pressure to the engine should the
engine driven fuel pump fail, and
secondly to provide pressurized fuel to
the primer solenoid for engine starting.
Fuel from the aircraft fuel system enters
the engine driven fuel pump and is then
routed to the carburetor fuel inlet.
The fuel tank vent system is designed to
keep fuel spillage to a minimum. The
fuel tanks are vented through tubing
connected at both the inboard and
outboard ends of the individual fuel tanks
to the centrally located vent system in the
fuselage. Ram air enters a vent scoop,
on the fuselage under the left wing and
pressurizes the vent system in order to
maintain positive pressure in the fuel
tanks. The vent system is provided with
two quick drains, located on the fuselage
side skins under each wing to drain any
fuel or condensation that might have
gotten in the tank's outboard vent lines.
The fuel quantity gauge is located on the
lower left instrument panel.
quantity indicating system consists of two
5-2
AIRCRAFT MAINTENANCE MANUAL
In each
fuel tanks are
The auxiliary fuel
The auxiliary fuel
The fuel
transmitters, one indicator gauge, and a
L/H or R/H tank fuel quantity selector
switch. A transmitter, installed in each
wing tank, transmits an electrical signal
to the single fuel quantity indicator. The
indicator reads either the left or right fuel
tank individually, as chosen with the tank
selector switch, adjacent to the fuel
quantity indicator
instrument panel.
Because of the geometry of the fuel
tanks and the fuel quantity transmitters,
the fuel quantity indicator needle reaches
its upper limit when the fuel tank contains
59 gallons of useable fuel. Another 7.5
gallons of useable fuel is in the tank
when it is topped off. Until the fuel level
in the tank falls below 59 gallons, one
cannot depend on the fuel quantity
indicator to indicate accurately how much
fuel remains in the tank. This is what is
meant by the placard on the indicator
that says "FUEL ABOVE 59 GAL IS
UNGAGEABLE".
The two fuel tanks are serviced through
filler ports located on the top of both
wings. The filler ports incorporate
security chains to prevent the loss of the
fuel caps. Service the aircraft from
refueling facilities that utilize proper
ground handling equipment and filter
systems to remove impurities and water
accumulations from the bulk fuel.
filtering facilities are not available, filter
the fuel through a quality high-grade
chamois. Fuel tanks should be serviced
after the last flight of each day to reduce
condensation and allow any entrapped
water accumulations to settle to the fuel
system drains. Prior to the next flight,
fuel should be drained from each wing
tank drain, the header tank drain, and the
firewall fuel filter, until all signs of water
are gone.
gauge on the
If
Effective: 01/01/08