What was found
ON APPROACH THE NR 1 AHRS (ATTITUDE HEADING REFERENCE SYS) UNIT OPERATED INTERMITTENTLY, THE UNIT RED FLAGGED THE HEADING AND WAS UNABLE TO ENGAGE THE FLIGHT DIRECTOR. THE CREW WAS UNABLE TO SWITCH THE NR 2 AHRS TO DRIVE THE NR 1 SIDE. AC PROCEEDED AND LANDED SAFELY WITHOUT INCIDENT, DID NOT DECLARE AN EMERGENCY. TROUBLESHOT SYSTEM AND FOUND THE NR 1 AHRS AHC-85E COMPUTER WAS AT FAULT. REMOVED AND REPLACED UNIT. COMPLIED WITH AHRS ADJUSTMENT/ TEST IAW MM. OPS CHECK GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE. (K) (EA25200507108)