Specifications

SECTION II
AIRPLANE AND SYSTEMS
MODEL 560
EMERGENCY BATTERY
Placing the battery switch in the EMER position opens the battery relay. The emergency bus relay
will remain closed. This disconnects the main direct current (DC) buses and the battery bus from the
battery and connects the battery directly to the emergency bus. With both generators offline, all electrical
equipment will be inoperative except COMM 1, NAV 1, the standby flight display, the standby horizontal
situation indicator (HSI), directional gyro number one, the N
1
tachometers, the standby pitot-static system
heaters, the voltmeter, the cockpit floodlights, the standby radio control head, RMU 1, landing gear control
and indication, flap control, pilot's and copilot's audio panels, and the interior entry lights. Emergency
lighting, in addition to the cockpit flood lights, which will be available are the instrument lights for the
standby gyro, the N
1
/ITT indicators, the standby HSI, and the standby flight display.
NOTE
The pilot should be aware that with both generators offline and the battery switch in
the EMER position, some of the more important items such as annunciator lights,
main pitot/static and angle-of-attack system heat, fire warning and fire bottle discharge
will be inoperative.
Going to EMER with either or both generators online will have no affect except that the battery will not
charge. As long as at least one generator is online, turning off the battery switch will not cause any
equipment on the emergency bus to cease functioning.
EXTERNAL POWER
External direct current (DC) power can be connected to the airplane through a receptacle located on
the left side of the fuselage. When external power is connected, the external power relay energizes and
connects the power source to the hot battery bus provided the generators are off line. When either
generator is on line, external power is disconnected from the battery bus. Positioning the battery switch to
BATT energizes the battery and emergency relays allowing external power to be connected to the entire
DC system. Ground power requirements dictate a 28-volt unit, with a maximum capability of 1000 amperes
current. If an adjustable power unit is used, it should be adjusted to provide a maximum of 1000 amperes.
A ground power unit with a soft start capability is preferable. The battery should be disconnected if the
airplane is to be on a ground power unit for a prolonged period of time.
CAUTION
CURRENT IN EXCESS OF 1000 AMPERES MAY DAMAGE THE STARTERS.
Starts being made on external power may be accomplished with the generator switches in either the
ON or OFF position; however, it is recommended that they be turned OFF during the start. If the generator
switch is placed in the ON position the generator control unit will automatically initiate the generator mode
after engine start. If the generator switch is placed in the OFF position, the generator mode will be initiated
by manually placing the generator switch to the ON position. External power is automatically disconnected
when either generator is supplying power to the bus. In order to start the second engine by auxiliary power
unit, the generator supplying voltage to the bus must be disconnected by placing the generator switch to
the OFF position.
An overvoltage protection system is provided during use of an auxiliary power unit. During an engine
start utilizing an external power unit, a control module monitors the external power unit voltage and will
deenergize the external power relay if voltage is above 32.5 volts. External power cannot be reapplied to
the airplane until the voltage has been interrupted after the start termination for the current protection or
until the voltage is reduced below 32.5 volts for the voltage protection.
For battery starts and under all normal flight conditions, the generators are left in the GEN position.
I 2-38 Configuration AA 56OMB-01