As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN LEVEL FLIGHT AT 6000 FT GEAR & FLAPS UP SPEED 250 KTS. WE GOT AN AMBER ALT BOX MESSAGE ON BOTH PFD'S AND AN EFIS MISCOMPARE ICAS MESSAGE. LEFT ALT (6000) RIGHT ALT (5850) STBY ALT (5800) RAN QRH AVNC 02-5 EFIS MISCOMPARE B3 CODE TO FOLLOW B3-007890 NO ADC-2 INPUT ON R-GP-5 CORRECTIVE ACTION: REMOVED AND REPLACED ADC #1 OPS CHECK GOOD IAW CL-350 AMM 34-13-01.