FAILED TO MAKE CROSSING RESTRICTION.

Narrative

TEN MI N OF DAYTON VOR WE WERE CLRED TO CROSS 50 MI N OF DAYTON AT FL240. THE COPLT FLYING COMPUTED THE DISTANCE FROM KLINE VOR SINCE WE HAD PASSED DAYTON. DURING THE DSCNT I RECALCULATED THE DISTANCE; THIS TIME FROM DAYTON; AND FOUND WE WERE 47 MI N AND PASSING FL260. I TOLD THE CTLR WE WOULD HAVE DIFFICULTY MAKING THE RESTRICTION AND ASKED IF A TURN WAS NECESSARY. HE ASKED WHAT THE REASON WAS FOR USE NOT STARTING DOWN SOONER. I INFORMED HIM WE HAD STARTED DOWN SOONER BUT HAD NOT DSNDED RAPIDLY ENOUGH FOR THE MISCALCULATION. HE TURNED US OVER TO CLE CENTER. THERE WAS NO CONFLICT OF TFC. I HAVE EXPERIENCED THIS XING CLRNC SEVERAL TIMES AND FEEL WE WOULD BE BETTER SERVED WITH A CLRNC BEFORE DAYTON VOR. OUR FMS COMPUTER INPUT IS MORE ACCURATE FOR VOR DOWN STREAM RATHER THAN PUTTING IN A VOR WE HAVE ALREADY PASSED. IT TAKES A COUPLE OF EXTRA ENTRIES TO PUT IN A VOR ALREADY PASSED AND IN SOME CASES THE BEARING PUT IN IS NOT AS ACCURATE A READING AS A DOWN LINE VOR. IN OTHER WORDS IT IS MUCH MORE EFFICIENT AND PRACTICAL TO KEEP ALL CALCULATION BASED ON DOWNLINE VORS RATHER THAN THOSE WE HAVE ALREADY PASSED.