What was found
PHX - DIVERTED FLIGHT - 2/14/01 - AFTER TAKEOFF FROM LAS TO BOS THE MCDU FROZE IN THE FLIGHT PLAN MODE; RNAV UNAVAILABLE; THE FLIGHT WAS DIVERTED TO PHX. IN PHX MAINTENANCE REPLACED THE LEFT AND RIGHT FMGC; AFTER REPLACEMENT, CURRENT NAV DATA WAS UPLOADED AND BITE CHECKS WERE GOOD. FMGC - SEXTANT, (P/N B398BCM0108), (S/N 1798), POS RIGHT, CONDITION UNRELIABLE, TT 16964, TC 8177, TSR 1244.