Learjet 20 Series Pilot Training Manual page 68

The battery may be used to power the following:
• Emergency attitude gyro and post light
• Gears
• Flaps
• Spoilers
• Emergency directional gyro and post
light
• Auxiliary communications and internal
light
• Pilot's audio panel
• Copilot's map light
• ADF
• Norm pitch trim
• Roll trim
• Yaw trim
• Nose steering
Operation
Under normal conditions, 28 VDC is being
supplied from the battery charging bus to the
emergency battery. The 28 VDC provides a
trickle charge for the emergency battery. When
the AUX. GYROS switch is placed to ON, 25
2A-22
LEARJET 20 SERIES PILOT TRAINING MANUAL
FOR TRAINING PURPOSES ONLY
VDC from the emergency battery is applied to
the pilot's audio panel, ADF, extra transceiver,
nosewheel steering relay, wheel master switch,
and trim systems (including the self-contained
inverter). The inverter system provides AC
power to the attitude and directional gyros.
Emergency Operation
Under an emergency mode of operation, the
auxiliary battery, through a diode network,
provides power to the pilot's audio panel,
ADF, transceiver, nosewheel steering relay,
wheel master button, directional and attitude
gyros, trim systems, copilot's map light, etc.
The momentary switch must be held to the
ON position when power is needed to operate
the gear, flaps, and spoilers. With all the above
equipment operating, the auxiliary battery
lasts approximately 15 minutes.
Optional Emergency
Battery System
An optional dry-cell nicad battery is provided
to power the standby attitude indicator through
a self-contained inverter and also to power an
auxiliary communications transceiver and the
gear, flaps, and spoiler solenoids (Figure 2A-
21). When illuminated, an amber light next to
the emergency battery switch indicates that the
emergency battery is supplying power.
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