SMA AND SMT; OPPOSITE DIRECTION ON SAME AIRWAY AT SAME ALT ARE ALLOWED TO COME INTO CONFLICT DUE TO CTLR BEING DISTRACTED TO ANOTHER PART OF HIS SCOPE.

Narrative

ACFT #1 (SMA X) WAS SEBND ON THE TERRE HAUTE 164 DEG R AT 6000'. ACFT #2 (SMT Y) WAS NWBND ON V243 (TERRE HAUTE 164 DEG R) AT 6000'. WHEN THE ACFT WERE APPROX 2 MI APART THE CTLR NOTED THAT THE ACFT WERE ON MERGING COURSES AND IMMEDIATELY ISSUED TURNS TO BOTH ACFT TO ACHIEVE SEP. ACFT #1 WAS ORIGINALLY ROUTED V171 AFTER TERRE HAUTE WHICH WOULD HAVE PROVIDED ADEQUATE SEP; BUT THE CTLR ISSUED A PREFERENTIAL ROUTING 40 MI PRIOR TO THE CONFLICTION POINT WHICH RESULTED IN THE INCIDENT. ACFT #1 WAS ALSO FLYING AT A WRONG ALT FOR DIRECTION OF FLT. THIS HAD BEEN APPROVED BY THE CTLR PRIOR TO THE CONFLICTION POINT WHICH RESULTED IN THE INCIDENT. ACFT #1 WAS ALSO FLYING AT A WRONG ALT FOR DIRECTION OF FLT. THIS HAD BEEN APPROVED BY THE CTLR PRIOR TO EITHER ACFT APPEARING ON THE RADAR SCOPE. BOTH ACFT APPEARED ON THE SCOPE AT ABOUT THE SAME TIME AT POINTS APPROX 100 MI APART. JUST PRIOR TO THE INCIDENT THE CTLR WAS BUSY WITH MULTIPLE APCHES AT THE PRIMARY ARPT. THIS; PLUS THE FACT THAT ACFT #1 OVERFLEW THE PRIMARY ARPT 12 MI PRIOR TO THE CONFLICTION AND THE DATA BLOCKS ON THE RADAR WERE OVERLAPPING CONTRIBUTED TO HIS FAILURE TO RECOGNIZE THE SITUATION AND RESOLVE THE CONFLICT. I FEEL THAT FUTURE OCCURRENCES OF THIS TYPE COULD BE AVOIDED BY REFUSING TO ALLOW ACFT TO TRANSITION THE AIRSPACE AT THE WRONG ALT. IN THIS SITUATION THERE WAS NO OPERATIONAL ADVANTAGE GAINED BY ALLOWING THE WRONG ALT FOR DIRECTION OF FLT. THE CTLR WAS JUST TRYING TO BE ACCOMMODATING TO THE PLT'S REQUEST. THE RESULT WAS AN OPERROR. ALSO; AT TIMES WHEN THE RADAR CTLR IS BUSY IT WOULD BE HELPFUL TO HAVE ANOTHER RADAR CTLR AVAILABLE AS AN EXTRA PAIR OF EYES TO HELP WITH THE SPOTTING OF POTENTIAL PROBS. IN CONCLUSION; I FEEL THAT THIS OPERROR RESULTED FROM THE CTLR'S ATTN BEING DIVERTED TO A DIFFERENT PART OF THE RADAR SCOPE AND BY HIS APPROVAL OF THE OVERFLT BY ACFT #1 AT THE WRONG ALT FOR DIRECTION OF FLT.