AN LR45 PILOT COMMENTS THAT THE ACFT'S DUAL FMS'S CANNOT SYNC. THE ACFT WAS HIGH ON A STAR BECAUSE HE MISPROGRAMMED THE FMS'S TO DISPLAY SEPARATE DSCNT TRACKS AND PROFILES. THEN HE FAILED TO VERIFY THE DSCNT REQUIREMENTS.

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DURING DSCNT ON THE ABC TWO STAR; ACFT WAS RECLRED DIRECT TO CDE WITH CLRNC TO CROSS AT FL240. FMS HAD BEEN PROGRAMMED PREVIOUSLY WITH ALL RESTRS ON THE STAR AND THE ACFT WAS ALREADY DSNDING WITH THIS XING RESTR IN MIND (AS VIEWED ON THE VERT TRACK DISPLAY). A DIRECT-TO WAS SELECTED; A VNAV DISENGAGED MESSAGE WAS POSTED ON THE FMS. A 'VERT DIRECT-TO' COMMANDED AND LNAV/VNAV WAS SELECTED. VERT SPD COMPUTED APPEARED APPROPRIATE TO MEET THE PLANNED FL240 XING. PASSING FL290; THE PM NOTICED THAT THE ACFT WAS APCHING CDE; AND THAT WE WERE WELL HIGH FOR XING AT FL240. AT THAT TIME I LOOKED AT THE FMS AND NOTICED THAT WE WERE PROCEEDING TO GHI INSTEAD OF CDE AND THE VNAV WAS TRACKING TO CROSS EFG AT 10000 FT; AS PROGRAMMED. I SELECTED FLC; REDUCED PWR TO IDLE AND INITIATED A MAX RATE DSCNT. ATC QUERIED ABOUT BEING ABLE TO MEET THE FL240 RESTR. ATC THEN RECLRED US TO EXPEDITE DSCNT AND CROSS CDE AT OR BELOW FL250. CAUSE: FAILURE OF PF (ME) TO CORRECTLY VERIFY THE WAYPOINT SELECTED WHEN THE DIRECT-TO WAS INITIATED ON THE PFD MAP DISPLAY AND MONITOR THE DSCNT. CONTRIBUTING FACTORS: LR45 WAS DUAL UNS 1 FMS'S; HOWEVER FMS'S ARE NOT SYNCED; BUT RATHER OPERATE INDEPENDENTLY. #1 FMS ON CAPT'S SIDE WAS THE NAVING FMS. #2 FMS DISPLAYS ON THE MFD MAP DISPLAY; WHICH IS USED NORMALLY USED FOR LATERAL SITUATIONAL AWARENESS. THE #2 FMS WAS CORRECTLY PROGRAMMED TO PROCEED DIRECT TO CDE AND DID HAVE THE SAME FL240 XING RESTR PROGRAMMED. THE PM WAS MONITORING THE PROGRESS; BUT NOTED THAT WHILE THE VNAV DISPLAY ON THE CAPT'S PFD (PF) SHOWED AN ON PATH INDICATION; HIS VNAV DISPLAY (COPLT'S PM) WAS SHOWING AN ABOVE PATH INDICATION. ON POSTFLT DEBRIEF; COPLT STATED THAT IT WAS NORMAL TO HAVE THE 2 FMS VNAV DISPLAYS DISAGREE BECAUSE OF DIFFERENT WAYS THE PF'S IN THE OP MANAGE AND PROGRAM THE 2 FMS'S. ONE FMS MAY BE PROGRAMMED TO CROSS A RESTR EARLY (FIX; 5 NM) OR MAY BE DSNDING ON A VERT DIRECT-TO; WHILE THE OTHER FMS MIGHT RETAIN THE ORIGINAL PROGRAMMED DSCNT ANGLE. MY OWN PERSONAL TECHNIQUE WAS TO ALWAYS HAVE BOTH FMS'S PROGRAMMED IDENTICALLY AND TO HAVE THEM NAVING BOTH LATERALLY AND VERTLY ON THE SAME PATH. HAD I NOT MISSED PROGRAMMED #1 FMS; THIS WOULD HAVE BEEN THE CASE. BECAUSE THE MFD (LOCATED ON THE R SIDE OF THE LR45 COCKPIT) IS LINKED TO THE #2 FMS; THE INCORRECT WAYPOINT SELECTION WAS NOT IMMEDIATELY APPARENT TO ME SINCE MOST OF MY REF WAS TO THAT MAP AND NOT MY PFD MAP (MY MISTAKE). THE 15 MI DISTANCE AND THE APCH FROM THE WNW TO BOTH CDE AND GHI MASKED THE DIFFERENCE IN DSCNT RATES TO CROSS THE FIX. ONLY THE VERY LATE CALL BY THE PM THAT IT APPEARED TO HIM THAT WE WERE NOT GOING TO MAKE THE CDE FL240 RESTR ALLOWED EVERYONE TO REGAIN SITUATIONAL AWARENESS (GOOD USE OF ADVOCACY ON HIS PART!). THE UNS FMS IS ONE OF THE FEW FMS SYS WHICH HAVE NOT HAD THE ABILITY TO SYNC AND OPERATE AS ONE. THE COLLINS SYS USED ON OUR OTHER ACFT HAVE THIS CAPABILITY; WHICH WOULD HAVE RESULTED IN THE SELECTION ERROR BEING NOTICED MUCH EARLIER. FURTHER; THE UNS DOES NOT HAVE A '2-STEP' CHANGE SELECTION PROCESS LIKE MOST OTHER FMS'S. THERE IS NOT AN EXEC KEY TO PRESS TO VERIFY SELECTED ACTION. A DIRECT-TO SELECTION IS IMMEDIATELY EXECUTED. IF THE WRONG WAYPOINT WAS SELECTED; THE ACFT WILL IMMEDIATELY BEGIN NAVING TO THE WAYPOINT. THIS MAKES WAYPOINT VERIFICATION MUCH MORE IMPORTANT IN THE UNS SYS. HAD THE COLLINS SYS; WITH ITS EXEC VERIFICATION FEATURE; BEEN THE FMS IN USE; I DON'T BELIEVE THAT THIS MISTAKE WOULD HAVE HAPPENED. THE UNS; IN ITS VERY LATEST SOFTWARE VERSION; HAS THE ABILITY OPERATE IN A SYNC MODE BTWN 2 FMS'S. THIS WOULD HAVE MADE THE INCORRECT WAYPOINT SELECTION IMMEDIATELY OBVIOUS TO THE PM ON HIS DISPLAYS AND ON THE MFD MAKING 'TRAPPING' OF THIS ERROR MUCH EASIER. HOWEVER; THE LEAR 45 DOES NOT HAVE AN STC OR UPGRADE OPTION FOR THIS VERSION OF SOFTWARE AS OF YET. IT IS ON A LIST OF CUSTOMER REQUESTED UPGRADES FOR THE LEAR 45. LESSONS LEARNED: VERIFY PER SOP'S ALL CHANGES PRIOR TO EXECUTING THEM. VERIFY THE PFD DISPLAYED 'TO' WAYPOINT AFTER ANY FMS NAV EXECUTION. MAINTAIN AN ACTIVE AND FREQUENT XCHK OF DISTANCE-VERSUS-ALT TO ENSURE THAT A XING RESTR WILL BE MET. WHEN FLYING AS PM; MONITOR THE PF'S PFD FOR PROPER INDICATIONS.