Garmin G1000 Reference Manual page 36

gps navigation
Altitudes associated with approach procedures are "auto-designated". This means
the system will automatically use the altitudes loaded with the approach for giving
vertical flight path guidance outside the FAF. Note these altitudes are displayed as
small light blue text.
Altitudes associated with arrival procedures are "manually-designated". This means
the system will not use the altitudes loaded with the arrival for giving vertical flight
path guidance until designated to do so by the pilot. Note that these altitudes are
initially displayed as white text. These altitudes may be "designated" by placing the
cursor over the desired altitude and pressing the ENT Key. After designation, the text
changes to light blue.
Altitudes that have been designated for use in vertical navigation may also be
made "non-designated" by placing the cursor over the desired altitude and pressing
the CLR Key. The altitude is now displayed only as a reference. It will not be used
to give vertical flight path guidance. Other displayed altitudes may change due to
re-calculations or rendered invalid as a result of manually changing an altitude to a
non-designated altitude.
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Garmin G1000 Cockpit Reference Guide for the Cessna Caravan
190-00748-02 Rev. B