As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT RELEASED BACK TO SERVICE AFTER EXPERIENCING A DIVERSION O R AIR TURN BACK DUE TO A MECHANICAL REASON LOCKED BY SYSTEM. AIR DATA INERTIAL REFERENCE UNIT - INSTALLATION, AMM REFERENCE: TASK 34-21-01-400-801, OPS CHECK OK. PERF LAND VERIFY TEST,AMM REFERENCE: TASK 22-11-00-700-801 ALL TESTS PASS, AC RETAINS FULL AUTOLAND CAPABILITES. REPLACING THE ADIRU WOULD SUFFICE WITH CORRECTING THE FAULT AND RETURN THE AIRCRAFT TO SERVICE .