Cirrus SR22 Pilot Operating Handbook page 207

Cirrus Design
SR22
precision airspeed indicator installed in the pilot's instrument panel.
The instrument senses difference in static and Pitot pressures and
displays the result in knots on an airspeed scale. A single pointer
sweeps an indicated airspeed scale calibrated from 40 to 220 knots.
The 'zero' index is at the 12 o'clock position. A sub-scale aligns true
airspeed with the corresponding indicated airspeed when the altitude/
temperature correction is set in the correction window. A knob in the
lower left corner of the instrument is used to rotate the pressure
altitude scale in the correction window to align the current pressure
altitude with the outside air temperature.
Serials 4164 & subs w/ MD302 Standby Attitude Module:
The MD302 Standby Attitude Module is mounted on the LH bolster
panel and displays the current Indicated Airspeed (IAS). The
instrument senses difference in static and pitot pressures and displays
the result in knots in the Airspeed Window. The Airspeed Window/
Pointer sweeps the indicated airspeed tape and denotes the current
airspeed. Color coded bars are provided to indicate flap operating
range, normal operating range, caution range, and never-exceed
speed.
28 VDC for the MD302 Standby Attitude Module is supplied through
the 5-amp STDBY ATTD 1 circuit breaker on the ESS BUS 1 and the
5-amp STDBY ATTD 2 circuit breaker on the MAIN BUS 1.
Altimeter
Primary altitude data is provided by the Air Data Computer and is
shown as a vertical tape along the upper right side of the PFD. The
altimeter scale is graduated with major tick marks at intervals of 100
feet and minor tick marks at intervals of 20 feet. Six hundred (600) feet
of barometric altitude is viewable at any time.
The local barometric pressure is set using the barometric adjustment
knob on the PFD. The selectable altitude reference bug is displayed
on the altimeter tape and is set using the altitude selection knob on the
Flight Management System Keyboard. Barometric minimum descent
altitude (MDA, or Decision Height, DH), can be preset. Altimeter trend
is also displayed as a bar along side of the altimeter tape.
The PFD Altitude is corrected for static source position error (normal
static source / 0% flaps), the altitude calibration errors for the PFD are
zero with flaps up and normal source (typical cruise flight). Calibration
corrections are only necessary when flaps are extended or the
alternate static source is selected.
P/N 13772-004 P/N 13772-004
Revision 1
Section 7
Systems Description
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