ZAU ARTCC RADAR CTLR LOST SEPARATION DURING OVERTAKE INCIDENT.

Narrative

SAW OVERTAKE ON SLOWLY CONVERGING RTES. TURNED SLOWER; FRONT ACFT 30 DEGS TO L AND FASTER; BACK ACFT 10 DEGS R; TO CROSS BEFORE OVERTAKE MADE IT TOO LATE. IT LOOKED LIKE I'D HAVE 5 NM BARE SEPARATION. CONFLICT ALERT ACTIVATED; BUT WAS MORE OF A DISTR IN THIS CASE BECAUSE IT WAS A CTLED SIT AND THE LAG INHERENT IN CONFLICT ALERT MADE IT UNRELIABLE. THE RULES REQUIRE 5 NM SEPARATION. IF A CTLR USES 5 NM SEPARATION AND IS COMFORTABLE WITH IT; AS I HAVE DONE MY ENTIRE CAREER; THEN ON RARE OCCASIONS HE OR SHE WILL COME UP A LITTLE SHORT. THE SIT DID NOT COMPROMISE SAFETY IN ANY WAY. THE SYS WORKED IN THIS CASE. WE MISSED BY 5 NM BECAUSE WE ARE HUMAN AND HUMANS MAKE MISTAKES. THE 5 MI RULE IS THE BUFFER. I AM GLAD IT IS THERE. YOU CAN'T TELL A CTLR TO GO FOR MORE SEPARATION THAN REQUIRED AND YOU CAN'T LOWER THE BAR WHEN THE BUFFER IS BREACHED. TELL US THE STANDARD; I'LL MAKE IT HAPPEN. UNFORTUNATELY; I AM HUMAN; I DO MAKE MISTAKES. THE BENEFITS OF HAVING A HUMAN IN THE LOOP FAR AND AWAY OVERSHADOW THE SIMPLE NEGATIVE. IN MY 13 YRS AS A RADAR CTLR; I CAN'T GUESS HOW MANY TIMES I HAVE EFFECTIVELY HANDLED SITS ALL WITH 100% ACCURACY. I DON'T PLAN TO CHANGE THE WAY I WORK IN ANY WAY. I AM THE BEST AT WHAT I DO. ANY REAL ATC CTLR WORTH A NICKEL WOULD SAY THE SAME. THE SYS IS SAFE.