What was found
ACFT WAS CONDUCTING A PART 91 FLIGHT. SHORTLY AFTER TAKEOFF, THEY LOST THE FLIGHT DIRECTOR AND THE FMS ON PIOTS SIDE. THE CREW ATTEMPTED TO RESET THE SYS, STILL UNABLE TO BRING THE FLIGHT DIRECTOR BACK UP. THE CREW MADE THE DECISION TO RETURN TO DEPARTURE. THEY LANDED WITHOUT INCIDENT. MG SWAPPED NR 1 AND NR 2 FLIGHT CONTROL COMPUTERS (FCC) AND PERFORMED SATISFACTORY FUNCTIONAL TEST. FOUND NR 2 FLIGHT MANAGEMENT COMPUTER (FMC) BAD. INSTALLED NEW FMC AND PERFORMED SATISFACTORY FUNCTIONAL TEST. (K)