System Malfunctions; Alternator Failure; Revision A5 - Cirrus SR22 Pilot Operating Handbook

Cirrus Design
SR22

System Malfunctions

Alternator Failure

Steady illumination of either ALT caution light in the annunciator panel
indicates a failure of the corresponding alternator. The most likely the
cause of the alternator failure is a wiring fault, a malfunctioning
alternator, or a malfunctioning control unit. Usually, electrical power
malfunctions are accompanied by an excessive rate of charge or a
discharge rate shown on the ammeter.
Alternators in this airplane are self-exciting. These alternators
require battery power for alternator starting; however, once
started, the alternators will provide self-generated field power
to continue operation in case of a battery failure. To assure
alternator restart power is available if the alternators fail, the
batteries should not be turned off during flight.
Serials 0002 thru 1643 and 1645 thru 1666: A flashing ALT 1 light
indicates an excessive charging rate. This could occur with a very low
BAT 1 and heavy equipment loads. Since the loads on ALT 2 are much
lower, it is unlikely that a flashing ALT 2 light could occur, even with a
very low BAT 2.
The Power Distribution Schematic shows the electrical system power
distribution. Individual loads on each circuit breaker panel bus are
shown in the same order as they are on the panel. Note that items on
the circuit breaker panel Essential buses are powered from ALT 1, ALT
2, BAT 1, and BAT 2. The circuit breaker panel Main buses and Non-
Essential buses are powered from ALT 1 and BAT 1 only.
If it is necessary to reduce electrical loads due to an alternator
malfunction, switch off electrical components and/or systems
that are not essential for the current flight conditions rather
than pulling circuit breakers. Load shedding in this manner will
prevent accidental circuit breaker disconnection and loss of
power to flight-critical systems. See Figure Electrical Power
Distribution, for details on electrical busses and what
components/systems they power.
P/N 13772-001
Revision A8
• Caution •
• Note •
Section 3A
Abnormal Procedures
3A-9