ACR X USING TCASII TA FOR VISUAL SEPARATION DURING VISUAL APCH OP.

Narrative

I WAS TRAINING A DEVELOPMENTAL ON ARR CTL. WE HAD AN ATX X FOR SEQUENCE TO VISUAL APCH RWY 15. THE DEVELOPMENTAL POINTED OUT ACFT Y AND THE PLT RESPONDED 'IS HE FOLLOWING SOMEONE OUT THERE AT 800 FT.' THE DEVELOPMENTAL WAS GOING TO CLR HIM FOR THE VISUAL APCH WHEN I STOPPED HIM AND ASKED THE PLT IF HE HAD ACFT Y IN SIGHT. HE SAID NOT VISUALLY BUT HAD HIM ON TCASII. THIS SEEMS TO BE HAPPENING MORE AND MORE AS THE ATX CREWS GET TCASII IN THEIR AIRPLANES. IT APPEARS THEY ARE USING TCASII INSTEAD OF LOOKING OUT THE WINDOW. AS AN AIR TFC CTLR I CANNOT HAVE PLT'S USING TCASII FOR VISUAL SEPARATION TO MAINTAIN SPACING AS ON 1 OCCURRENCE A CREW OFFERED TO DO. THERE IS NO TCASII SEPARATION! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED IT IS THE ATX/COMMUTER FLC'S THAT RPT HAVING ACFT IN SIGHT ON TCASII. RPTR STATED SEVERAL OTHER CTLRS HAVE SAID THEY HAVE THE SAME PROBLEM WITH COMMUTERS. RPTR THINKS WITH TCASII BEING NEW TO ATX/COMMUTERS THE FLC'S BELIEVE THEY WILL GET THE CLRNC FOR A VISUAL APCH SOONER IF THEY RPT THE ACFT IN SIGHT BY TCASII AND NOT VISUALLY SIGHTING THE TFC THEY ARE FOLLOWING.