What was found
WHILE FLYING IN IMC ENROUTE FROM JVY TO OWB, THE ATTITUDE, HEADING, REFERENCE SYSTEM AND AUTOPILOT FAILED IN FLIGHT. AT THE TIME OF THE FAILURE, THE AIRCRAFT WAS LEVEL AT 6,000 FT, AT 220 KIAS AND COUPLED TO THE AUTOPILOT IN NAV MODE AND ALTITUDE HOLD. PILOT DECLARED AN EMERGENCY, DESCENDED TO VMC AND RETURNED TO JVY. ATTEMPTED TROUBLESHOOTING DID NOT FIND ANY DISCREPANCIES AT THIS TIME.