Fuel System - Thrush Aircraft S2R–T660 Maintenance Manual

THRUSH AIRCRAFT INC – T660 TURBO THRUSH
AIRCRAFT MAINTENANCE MANUAL
There are five links from the servo-piston. One goes to each blade root, and these links transmit
forward motion of the servo-piston to the blade roots and pivot the blades in the decrease pitch
direction. When servo-piston pressure is relieved, the servo-piston moves rearward under feather
return spring pressure and pivots the blades in the increase pitch direction. This action is assisted
by centrifugal force of the counterweight on each blade root.

FUEL SYSTEM

A 230-gallon fuel supply is available for the Thrush S2R-T660. In each wing, fuel is contained inside
integral wing tanks (wet wing fuel tanks) just outboard of the center section sub-wings. The left wing
and right wing fuel tanks are interconnected through a 5 U.S. gallon header tank that is located in
the fuselage. The fuel supply lines, to the engine, are routed from the header tanks outlet finger
screen through a fuel shutoff (on/off) valve to an electric driven fuel boost pump. The electric driven
fuel boost pump discharge is then routed through a 25-micron main fuel filter to an engine driven
fuel boost pump. The electric driven fuel boost pump serves two purposes, first as a backup system
to provide continuous fuel pressure to the engines high pressure fuel pump in case the engine
driven fuel boost pump fails and secondly to provide boosted fuel pressure to the engines high
pressure fuel pump during engine starting. The aircraft's fuel system is equipped with two fuel
filters, a ¼ inch mesh finger strainer is installed in the outlet fitting from the header tank and a 25-
micron, airframe supplied, main fuel filter located on the forward L/H side of the firewall. Fuel from
the aircraft fuel system enters the engines high pressure fuel pump which has two fuel filters, an 74-
micron inlet filter and a 10-micron discharge filter (refer to the engines appropriated maintenance
manual for pertinent maintenance details for the engine supplied filters and fuel system). The fuel
tank vent system is designed to keep the 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 to maintain positive pressure on the fuel tanks. The
vent system is provided with two quick drains, located on the fuselage under each wing, to drain
any fuel that might happened to have got in the tanks outboard vent lines. At engine shutdown, fuel
from the flow divider/dump valve, located at the 6 o'clock position on the engines fuel nozzle
manifold, is directed to a residue fuel reservoir "EPA tank" mounted inboard on the L/H aft shin skin.
This reservoir hold approximately 3 engine shutdowns worth of fuel before the fuel will exit the
reservoirs vent system. (NOTE: This reservoir should be emptied after each engine shutdown.)
(NOTE: It is common and normal after an engine compressor Water Wash or Performance
Recovery Wash to have water or soap appear in the reservoirs' drained waste fuel.) The fuel
quantity gauge is located on the lower left instrument panel. The fuel quantity indicating system
consists of two transmitters, one indicator gauge, and a L/H or R/H tank fuel quantity selector
switch. A transmitter, installed in each wing
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Effective: 12/17/03