Cirrus SR20 Pilot Operating Handbook page 364

Section 9
Supplements
Serials w/ Discrete-Triggered Low Speed Mode (Optional)
To protect against an impending stall, the Discrete-Triggered Low
Speed Mode uses stick forces, similar to those used for the pitch and
roll modes, to control the pitch attitude. These stick forces are
triggered by the stall warning system. Upon stall warning system
activation, the system commands the pitch servo to apply a nose-
down supplemental force. The maximum stick force is attained
approximately 1.5 seconds after the stall warning signal is activated,
and is maintained as long as the stall warning system is active. If the
stall warning system becomes inactive, the supplemental force is
smoothly removed over approximately 2 seconds.
Low Speed Protection
0
Engagement Limit: ......................................................Stall warning
Maximum Stick Force attained at: .. 1.5 seconds after stall warning
Disengagement Threshold: ..................... Stall warning deactivated
Zero Stick Force:............ 2 seconds after stall warning deactivated
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).
26 of 32
2 4
Time (sec)
ESP Force
Stall Warning
6 8
Revision 03: 09-08-14
Cirrus Design
SR20
10
P/N 11934-S41