As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT WAS DISPATCHED WITH NR 3 ADR INOPERATIVE. AFTER DEPARTURE IN THE CLIMB, THE FLIGHT EXPERIENCED A FAILURE OF THE NR1 ADR AND ELECTED TO RETURN. NO EMERGENCY WAS DECLARED. THERE WAS NO ADVERSE PASSENGER REACTION OBSERVED REPLACED ADIRU 1 IAW AMM TASK 34-12-34-400.