arinc to efis

[sneedrv-6]

I have 2 AFS 3500's Garmin 430w and the Digiflight IIVGS autopilot. The garmin connects to the Arinc then the Arinc is connect to the PFD. If the PFD dies I can not shoot an approach with the MFD. Can someone tell me why I can't hook the Arinc up to both the PFD and the MFD even if I did it through a switch? This way if I was to loose the PFD I could flip the switch and fly an approach with the mfd. I also have dual ARHS.

Thanks,

Jason

[grover]

if you mean the arinc coming out of the 430, it should work in parallel to the 2 efis's fine. unless in some bizarre failure mode one of the arinc recievers shorted to ground or something odd.