What was found
DURING FLIGHT BOTH FMC CDU'S WENT INTO MENU MODE FOLLOWED BY CAPTAINS AND FIRST OFFICERS INBOARD CDU'S BY BOTH SHOWING VTK AND MAP FLAGS. AFTER 30 SECONDS ALL FLAGS DISAPPEARED AND THE FMC'S BOTH SHOWED NORMAL. IT APPEARS THAT ALL SELF-CORRECTED BEFORE QRH COULD BE CONSULTED. GROUNDED - YES. PERFORMED FMCS BITE ON L/H AND R/H FMC'S PER B737-900 FIM 34-61 TASK 801 AND FOUND FMC L CLOCK DATE FAULT. PERFORMED FIM 34-61 TASK 829 WITH NO FAULTS. NO HISTORY PAST 30 DAYS.