As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 6276 - IAD-EWR - DURING CRUISE, RETURNED TO IAD DUE TO THE LOSS OF RELIABLE AHRS INFORMATION ON BOTH SIDES. AIRCRAFT RETURNED TO IAD WITH NO FURTHER INCIDENTS. MAINTENANCE REPLACED THE DIGITAL AIR DATA COMPUTER. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)