As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE ACFT TOOK OFF & WHILE IN CRUISE THE COPILOTS AHRS FAILED, CAUSING THE LOSS OF HEADING & ATTITUDE, THE REVERSIONARY SYS WAS USED. THE PILOTS MADE THE DECISION TO DIVERT & A TECHNICIAN WAS DISPATCHED TO THE ACFT & IT WAS DETERMINED TO BE A FAULTY AHRS UNIT. THE PART WAS REPLACED & INSTALLATION PROCEDURES WERE FOLLOWED. OPERATIONALLY CHECKED & THE ACFT RETURNED TO SERVICE.