What was found
CREW REPORTED THAT DURING DESCENT RECEIVED AN AUTOPILOT FAIL MESSAGE. WHILE REFERENCING THE QUICK REFERENCE HANDBOOK, CREW THEN RECEIVED PITCH TRIM MAIN AND PITCH TRIM BACK-UP INOP MESSAGES ON THE EICAS. THE CREW REGAINED USE OF THE AUTOPILOT SYSTEM. THE CREW ALSO REPORTED A FLUTTER DURING PITCH CHANGES, RECEIVED A SPS ADVANCED MESSAGE, GPWS FAIL, AND AN INDICATION AIRSPEED MISCOMPARE. THE CREW DECLARED AN EMERGENCY AND RECEIVED VECTORS STRAIGHT TO KCHS. THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE HORIZONTAL STABILIZER CONTROL UNIT AND PERFORMED SUCCESSFUL OPERATIONAL CHECKS OF THE GPWS, AIRSPEED INDICATOR, AUTOPILOT SYSTEM, AND THE STALL PROTECTION SYSTEM. THE AIRCRAFT COMPLETED A SUCCESSFUL TEST FLIGHT AND NO FURTHER DEFECTS WERE NOTED.