As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL - FLT 704 - CLT TO FRA - PRIOR TO COAST OUT, RECEIVED 'NAV IR3 FAULT'. FLIGHT COULD NOT CONTINUE ETOPS PER PROCEDURES. FLIGHT DIVERTED TO PHL AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE ADIRU NUMBER 3. OPERATIONALLY CHECKS OK.