Avidyne IFD540 Pilot's Manual page 105

The Charts Selection page presents a list of available charts.
Use the right-hand knob on the IFD to select the desired
approach from the presented list and push the knob in, or touch
the desired approach in the list, to select and display the chart.
NOTE
Inclusion of RNP Approach Choices
RNP approaches may be included in the list of
available charts and can be selected for viewing but
they cannot be selected in the FMS, and the IFD
system is not authorized for RNP operations.
Chart Extent Box
A green chart extent box is drawn separately on the map and
represents the geographic boundaries of an instrument approach
plate associated with a FMS destination. When the ownship
symbol crosses the boundary of the chart extent box, this is a
good time to switch over to the CHART tab.
Close Up of Chart Extent Box
Map Pages 3-29