As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON APPROACH TO KLWB, PILOT AND COPILOTS FMS FAILED 3 TIMES. DID NOT RECOVER AFTER THE 3RD TIME. DIVERTED TO KROA. LANDING WAS UNEVENTFUL. MAINTENANCE TROUBLESHOT THE DISCREPANCY TO A FAULTY GPS-400S UNIT. THE GPS-4000S WAS REPLACED. GROUND OPERATIONAL CHECK ACCOMPLISHED WITH NO FURTHER DEFECTS NOTED. AIRCRAFT WAS RETURNED TO SERVICE.