Avidyne IFD540 Pilot's Manual page 35

Shared Data (Dual IFD Operations)
The following list of data will be shared between two IFDs if
properly configured for data sharing:
 Enables the integration of the Caution Alerting
System (CAS) to allow a single acknowledgement
of any of the Global messages to be removed from
both units by acknowledging them on either unit;
 Enables flight plan synchronization, including
modification of the flight plan to be reflected on
both IFDs (this does allow for flight plan/procedure
preview on the second IFD);
 Enables stored routes to be synchronized across
both IFDs (this does allow for route preview on the
second IFD);
 Enables fuel planning (e.g. initial fuel entry) to be
synchronized across both IFDs;
 Enables user waypoints to be synchronized across
both IFDs;
 Enables sensor settings and data (traffic, datalink,
lightning, air data, etc) to be shared across both
IFDs.
NOTE
Full Data Sharing Requires Consistent WAAS
For complete data sharing between dual IFDs, both
units will need to have the same WAAS antenna
configuration – either both are WAAS or both are
non-WAAS. If one IFD is set up with a WAAS
antenna and one is set up with a non-WAAS
antenna, then the FMS-related data (flight plans,
waypoints, routes) will not be shared between IFDs.
System Overview 1-29