As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED UPON ARRIVAL TO DFW DUE TO NAV IR 1 FAULT. THE AIRCRAFT LANDED SAFELY AT DFW WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE #1 AIR DATA AND INERTIAL REFERENCE UNIT (ADIRU) PER AMM 34-12-34. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.