As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT, EFIS COMP MON CAUTION WITH IAS FLAG. LEFT AND RIGHT SIDE HAD 10 TO 15 KT SPLIT, C/W QRH MSG PERSISTED. LEFT AIRSPEED DROPPED TO 160 KTS, ACFT SPEED WAS 300 KTS. REMOVED AND REPLACED NR 1 ADC IAW AMM 34-13-01. OPS CHECK GOOD AND FUNCTION CHECK GOOD.