I got the information from Aspen Avioncs that the ARINC429 interface
of the KLN900 cannot be used by the EFD1000. Does anyone has an idea
why? is it a technical problem or a certification problem? EFD1000 can
use the Garmin ARINC.

The EFD1000 has an internal AHRS which provides attitude + other
informations. Why this internal attitude (solid stade, certified and
more stable than the one provided by a gyro) cannot be used to provide
the attitude to an autopilot, the "old" gyroscopic reference has to
remain for the autopilot. This seems a real non sense to me.

Thanks for any info on this matter.

Denis