As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOST ADC NR 1 INFORMATION DURING CLIMBOUT, SWITCHED TO ADC NR 2 INDICATIONS NORMAL. C/W QRH, PERFORMED AIR RETURN TO DEPARTURE. LANDED AT 47.200 LBS, 300 FT/MIN. BRAKE TEMPS READ 5-5-5-6. FOUND AIR DATA REF PANEL NR 2 TO HAVE NO OUTPUT TO AIR DATA COMPUTERS. REMOVED AND REPLACED ADRP NR 2 IAW AMM 34-10-00. OPS CHECK OF NR 1 AND NR 2 AIR DATA SYS ARE GOOD. (K)