As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT THE CAS SYS INDICATED THAT THE RUDDER BOOST SYS WAS INOPERATIVE. TROUBLESHOOTING IDENTIFIED THAT THE NR 2 AHRS HAD FAILED. THE FAILED UNIT PN HG2010AC02, SN 97040504 WAS REMOVED & A TESTED UNIT WAS INSTALLED.