As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6621 - IAD-ILM - DURING CRUISE, AIRCRAFT MADE AN UNSCHEDULED LANDING DUE TO NR 2 ADC FAILURE. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND REMOVED AND REPLACED NR 2 ADC, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)