Learjet 60 - Auxiliary Power Unit (APU) Generator; EMER BAT Switch

Pilot’s Manual Learjet 60
4-20 PM-123
Change 6
EMER BAT SWITCH
The EMER BAT switches have two positions: On (EMER BAT 1, 2, 3)
and OFF. With a switch in the On position, electrical power from the
corresponding emergency power supply battery is available to supply
emergency power should the normal electrical system fail. Normally,
electrical power from the emergency power supply batteries is not used
because 28 VDC from the normal electrical system is balanced against
it. In the event of a failure of the normal electrical system, the balanced
condition is removed and electrical power from the emergency power
supplies will illuminate the EMR PWR annunciators, and operate the
standby attitude indicator, N
1 indicators, selected instrument lights
(standby attitude indicator, N
1 indicators, standby airspeed indicator,
standby altimeter, and magnetic compass), landing gear position lights,
NAV 1, RTU 1, COM 1, FMS 1 and AHS 1 & 2. Additionally, ADC 1 & 2
will be powered up while the EMER BUS switch remains in
the NORMAL position.
AUXILIARY POWER UNIT (APU) GENERATOR
The optional APU generator provides 28 volts DC electrical power to
the aircraft battery charging bus. The generator is controlled by a Gen-
erator Control Unit (GCU). The APU is only certified for ground use.
After starting the APU using the APU control panel on the copilot’s cir-
cuit breaker panel, the green APU RUNNING annunciator will illumi-
nate indicating that the APU system is ready to supply power to the
aircraft. Refer to Auxiliary Power Unit in Section II of this manual.
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