Garmin CIRRUS PERSPECTIVE SR20 Line Maintenance Manual page 212

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Due to the difficulties in executing smooth and accurate turns, the
PFD may incorrectly interpret a station and instruct to "HOLD
POSITION" prior to full completion of a 30° turn. If this scenario
occurs, ignore the "HOLD POSITION" command and use outside
references to complete the approximate 30° turn. Instead of
using the PFD instruction to turn as a real‐time indication of when
to turn, simply judge the 30° (±5°) turn increments of the aircraft
by using the compass rose radials. Dwelling at these 30°
increments for the time recommended by the PFD should result in
successful calibration. The PFD guides the operator to dwell at
multiple headings around a complete circle.
Due to high winds or excessive airframe vibration, the operator
may encounter a condition where the PFD restarts the 18‐second
countdown without full completion of the previous countdown. If
this occurs more than once for a given station, begin turning to
the next station (approximately 30°). A minimum of two
successful stations according to a quadrant is required, where a
successful station is a full 18‐second countdown followed by
instruction to move. Ensure that at least two stations according
to a quadrant are completed. It may sometimes be required to
dwell at a station after a countdown restart. A maximum of 30
stations is allowed for the entire calibration procedure. If too
many countdown restarts occur, the calibration will fail and the
message 'TOO MANY STATIONS' is displayed.
Aircraft rocking from excessive winds may prevent the calibration
test from passing. If repeated attempts in windy conditions do
not pass, wait until the winds calm before reattempting the
procedure.
12. Repeat the turn‐and‐stop process until the PFD advises that a successful calibration is
complete. The GRS 77 AHRS then enters its normal operational mode. Press the ENT
button on the PFD to conclude the procedure.
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Cirrus Perspective™ Line Maintenance Manual
190-00920-00