As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6598 - IAD-RUD - ABORTED TAKEOFF DUE TO NR 1 EADI FAILURE. AIRCRAFT RETURNED TO GATE WITH NO FURTHER INCIDENTS. MX REMOVED AND REPLACED NR 1 AHRS COMPUTER, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)