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P/N 13772-135
Section 9
Cirrus Design
Supplements
SR22 / SR22T
Underspeed Protection Mode (Optional)
When installed, to discourage aircraft operation below minimum
established airspeeds the AFCS will automatically enter Underspeed
Protection Mode when the Autopilot is engaged and airspeed falls
below the minimum threshold. If aircraft stall warning system is not
operational, autopilot underspeed protections that depend on that
system will also not be functional (affects altitude critical modes only:
ALT, GS, GP, TO, and GA).
As described in the following table, when the aircraft reaches
predetermined airspeeds a yellow MINSPD annunciation will appear
above the airspeed indicator and a single aural “AIRSPEED” will
sound to alert the pilot to an impending underspeed condition.
The system differentiates two types of vertical modes based on which
vertical Flight Director mode is selected; Altitude-Critical - where
terrain hazards are more probable and minimized altitude loss is
critical and Non-Altitude Critical - which generally correspond with
activities that can afford exchange of altitude for airspeed without
introducing terrain hazards.
Altitude-Critical Mode (ALT, GS, GP, GA, TO)
Upon stall warning system activation, the AFCS will abandon its Flight
Director and Autopilot reference modes and sacrifice altitude for
airspeed. The system will hold wings level and airspeed will
progressively increase by 1 knot per second until stall warning
becomes inactive. The system will then increase airspeed an
additional 2 knots above the speed at which the stall warning
discontinued. Recovery may be initiated in one of three ways:
1. Add sufficient power to recover to a safe flight condition.
If a small power addition is made, the AFCS will pitch the aircraft
to maintain speed reference. If a large power addition is made the
AFCS recognizes it via acceleration and the AP/FD will transition
Anti-Ice System Flaps
MINSPD
Annunciations
Aural Alert
Annunciations
OFF
0%
80 KIAS
85 KIAS
50%
76 KIAS
80 KIAS
100%
70 KIAS
80 KIAS
ON
0%
85 KIAS
90 KIAS
50%
81 KIAS
85 KIAS
Revision 03: 12-14-10
