What was found
FLIGHT ATN107, ENROUTE FROM KCVG TO KHRL CREW REPORTS AUXILIARY POWER PLANT (APU) FAULT EICAS MESSAGE DISPLAYED. LEFT INTEGRATED DRIVE GENERATOR DEFERRED. IAW ATI QUICK REFERENCE HANDBOOK, TRIED TO RESTART AUXILIARY POWER PLANT, CONVERSELY, THE SYSTEM FAILED TO START. PER ATI QUICK REFERENCE HANDBOOK , DIVERSION TO CLOSEST SUITABLE AIRPORT REQUIRED. DIVERSION TO KBNA WITH EMERGENCY DECLARATION. LANDING WAS UNEVENTFUL WITH NO ADDITIONAL PRECAUTIONARY ACTIONS. AIRCRAFT GROUNDED FOR UNSCHEDULED MAINTENANCE. WORK IN PROGRESS.