High Or Low Voltage On Essential Bus; Revision A1 - Cirrus SR20 Pilot Operating Handbook

Cirrus Design
SR20

High or Low Voltage on Essential Bus

ESS BUS Warning
1. Essential Bus Voltage (ESS).............................................. CHECK
If Essential Bus Voltage is greater than 32 volts:
2. Main Bus 1 and Main Bus 2 Voltages (M1 and M2)........... CHECK
3. Perform appropriate
checklists.
If Essential Bus Voltage is less than 24.5 volts:
4. Perform ALT 1 Caution (Failure)
Checklists
If unable to restore at least one alternator:
5. Non-Essential Loads........................................................ REDUCE
a. If flight conditions permit, consider shedding:
Air Conditioning, Landing Light, Pitot Heat, Cabin Fan, Nav
Lights, Strobe Lights, Audio Panel, COM 2.
6. Land as soon as practical (Battery reserve only)
Amplification
Dependent on battery state, flaps and landing light may be
unavailable on landing.
Essential Bus voltage is high or low. High voltage indicates alternator
voltage regulator failure; will typically be associated with high M1 and/
or M2 voltages and M BUS 1 and/or M BUS 2 warning messages.
Low voltage indicates dual failures of Alternators 1 and 2, will typically
be associated with low M1 and M2 voltages, M BUS 1 and M BUS 2
Caution messages, and Alt 1 and Alt 2 Caution messages.
P/N 21399-004 P/N 21399-004

Revision A1

ESS BUS
M BUS 1 Warning
and
• Caution •
Emergency Procedures
or M BUS 2 Warning
ALT 2 Caution (Failure)
Section 3
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