7-16 FUEL SYSTEM
The airplane fuel system consists of two vented, integral fuel tanks, shutoff
valves, a fuel selectors off warning system, fuel reservoir, ejector fuel pump
(jet pump), electric powered auxiliary fuel boost pump, rewall fuel shutoff
valve, rewall mounted fuel lter, oil-to-fuel heater, engine driven fuel
pump, fuel control unit, ow divider, dual fuel manifolds, and 14 fuel nozzle
assemblies. An oil/fuel reservoir drain is also installed. Refer to “Section 2” of
this manual for fuel quantity data for the system.
Fuel ows from the tanks through the two fuel tank shutoff/selector valves
at each tank. The fuel tank shutoff valves are mechanically controlled by
two fuel shutoff valve controls, labeled LEFT, ON and OFF and RIGHT, ON
and OFF. The fuel tank shutoff/selector valve controls are installed on the
overhead panel. By actuating the controls, the pilot can select either the left
or right fuel tank, or both at the same time. Normal operations are conducted
with both selector valves in the ON position. Fuel ows by gravity from the
shutoff valves in each tank to the fuel reservoir. The reservoir is located
in the bilge area of the fuselage, and is at the low point of the fuel system.
The reservoir maintains a head of fuel around the ejector pump which is
contained in the reservoir. This head of fuel helps prevent engine driven fuel
pump cavitation in low-fuel quantity situations, especially while maneuvering
the aircraft in ight. The ejector pump is driven by motive ow from the fuel
control unit and provides fuel ow from the reservoir to the engine driven
pump when the engine is running. The auxiliary fuel pump is installed
just forward of the fuel reservoir and is used to supply fuel to the engine
during starting or if fuel pressure from the ejector pump is reduced below
approximately 4 psi. Fuel from the ejector pump and auxiliary fuel pump ows
into a fuel manifold. From the fuel manifold, the fuel then ows through a
rewall fuel shutoff valve located on the aft side of the rewall. This shutoff
valve allows the pilot to cut off all fuel to the engine.
After passing through the rewall fuel shutoff valve, the fuel is routed through
a lter mounted on the forward side of the rewall. The fuel lter incorporates
a bypass feature which allows fuel to bypass the lter in the event the lter
becomes clogged with foreign debris. The lter is equipped with a red lter
bypass ag on top of the lter which protrudes upward when the lter is
bypassing fuel. Fuel from the lter is then routed through the oil-to-fuel heater
to the engine-driven fuel pump where fuel is delivered under pressure to the
fuel control unit. The fuel control unit meters the fuel and directs it to the ow
divider which distributes the fuel to the dual manifolds and 14 fuel nozzles
located in the combustion chamber. Fuel remaining in the engine fuel nozzle
manifold at shutdown drains into a canister (EPA can) located on the lower,
forward left portion of the rewall or on the lower left cowl. The can should be
drained during preight inspection of the aircraft to prevent can overow.
WARNING: Unusable fuel levels were determined for this airplane in
accordance with the Federal Aviation Regulations. Failure to operate the
airplane according to the Fuel Limitations outlined in “Section 2” of this
manual may further reduce the amount of fuel available for ight.
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