Specifications

SECTION II
MODEL 560 AIRPLANE AND SYSTEMS
FUEL
GENERAL
The Citation Encore fuel system is made up of two distinct, but essentially identical halves. Normal
operation supplies fuel to the engine from its respective integral wing tank. Each half of the system holds
approximately 403 U.S. gallons for a total airplane capacity of 806 gallons of usable fuel (approximately
5440 pounds). Crossfeed capability is incorporated, and when selected, enables both engines to receive
fuel from a single tank. The single-point pressure refueling receptacle, is located on the right side of the
fuselage, aft of the wing. It permits simultaneous servicing of both sides of the fuel system. Refer to the
Maintenance Manual, Chapter 12 for fuel servicing procedures.
System operation is fully automatic throughout the normal flight profile. Fuel system control and
monitoring is available through the boost pump switches, crossfeed switch, fuel quantity and flow indicators,
and annunciator panel lights which warn of abnormal system operation. A low fuel level warning system
functions independently of the normal fuel quantity indicating system.
FUEL CELL
Each tank encompasses the internal wing area forward of the rear spar except for the gear well,
inboard to the wing root and outboard to the wing tip fairing. An electric boost pump, primary ejector pump,
four transfer ejector pumps and seven fuel quantity probe assemblies are internally incorporated. A sump
area in each saddle tank includes the electric boost pump, primary ejector pump and quick drains to
preclude water and sediment buildup. The sump itself is designed to provide a minimum of five seconds
fuel supply during negative gravity maneuvers not exceeding -0.5 G. Fueling is accomplished through an
overwing port in each cell, or through the pressure refueling system.
A vent system ensures ambient pressure within the tank and fuel expansion overflow capability. A
float-type valve restricts flow through the vent during inflight maneuvering. Design features of the vent
prevent it from becoming blocked by inflight ice accumulation.
ELECTRIC BOOST PUMP
The electric boost pump provides fuel pressure for engine starting, crossfeeding and acts as a backup
for the primary ejector pump. Operation is indicated by illumination of the L or R FUEL BOOST annunciator
panel lights.
The pumps are controlled by a pair of three-position switches located on the left switch panel. The
switches are marked OFF, NORM and ON. In the OFF position, the boost pump is deenergized. In NORM,
function is automatic for start and crossfeed, and is activated by the pressure switch should output from the
primary ejector pump be insufficient. The respective boost pump when in OFF or NORM is disabled any
time the throttle is in cut-off, to preclude pump activation by low pressure sensing during shutdown. The
ON position causes the selected pump to operate continuously regardless of throttle position.
To ensure uninterrupted fuel flow to the engines, the boost pump switches must be positioned ON
when the low fuel lights illuminate or at 180 pounds or less indicated fuel.
I 56OMB-01 Configuration AA 2-15