Cirrus SR22 Pilot Operating Handbook page 365

Cirrus Design Section 9
SR22 Supplements
ALT (Altitude) – The ALT button has two functions: Altitude Pre-select
and Altitude readout.
Pre-select - When the ALT button is pressed while the system is in the
Data Entry (DTA) mode the SEL annunciator will flash and a new
altitude can be selected by rotating the input knob CW to increase
altitude and CCW to decrease altitude in thousands of feet. Pull the
knob to input altitude in hundreds of feet. For example: 5500 feet is
input as 5.5. Pressing DTA again will return the system to 'operate'
mode and the SEL annunciator will stop flashing with the ALT
annunciator remaining on. When a preselect altitude is coupled to the
autopilot by pressing and holding the VS button and then pressing the
ALT button, the airplane will fly at the selected vertical speed until the
selected altitude is intercepted. At that time the altitude selector will
command the autopilot to engage altitude hold.
Readout – When the ALT button is pressed in the 'operate' mode, the
SEL annunciator will go out and the display will show the baro
corrected encoder altitude. Repeated pushes of the ALT button will
alternately display baro corrected encoder altitude and pre-selected
altitude.
ALR (Alert Mode) – The ALR button enables the altitude alert system
in conjunction with the ALT SEL mode. Pressing the ALR switch
illuminates the ALR annunciator indicating arming of the alert mode.
Upon entering within 1000 feet of the altitude selected in ALT SEL, the
altitude alert chime will sound in the cabin speaker and headphones
and the ALR annunciator will flash. The chime will sound and the ALR
annunciator will flash again as the airplane approaches within 300 feet
of the selected altitude. If the airplane's altitude deviates ± 300 feet
from the selected altitude, the chime will sound and the ALR
annunciator will flash to indicate the condition. The ALR function can
be alternately enabled and disabled by repeatedly pressing the ALR
button.
P/N 13772-108 23 of 24
Revision 06: 05-09-11