What was found
IAD/ORF - FLT 6285 - DURING TAXI-OUT ON 10-28-97 AT 1100 HOURS, CREW EXPERIENCED A DISCREPANCY WITH THE NR 1 AHRS NOT INDICATING CORRECTLY. THE AIRCRAFT RETURNED TO THE GATE WHERE MAINTENANCE WAS DISPATCHED AND THROUGH TROUBLESHOOTING, FOUND THE NR 1 AHRS WAS INOPERATIVE CAUSING A 40-DEGREE SPLIT. MAINTENANCE REMOVED AND REPLACED THE NR 1 AHRS AND PERFORMED THE REQUIRED FUNCTIONAL TESTS. AIRCRAFT WAS THEN RELEASED FOR SERVICE. (X)