As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED, THE STANDBY ATTITUDE-AIRSPEED AND ALTITUDE MISSING RED X. THE MAINTENANCE VENDOR DETERMINED THE FLIGHT GUIDANCE AIRDATA COMPUTER WAS AT FAULT. THE DEFECTIVE UNIT WAS REMOVED AND REPLACED WITH A REPAIRED UNIT. THE AIRCRAFT WAS THEN RETURNED TO SERVICE.