ORD LCL CTLR ISSUES TKOF CLRNC TO AN A320 WITH TFC ON SHORT FINAL. LNDG TFC ADVISES IT WILL EXECUTE A GAR AS A320 QUICKLY ACCELERATES FOR TKOF. TFC LANDS.

Narrative

WE (X) WERE HOLDING SHORT OF RWY 22L AT ORD. ACFT WERE TAKING OFF AND LNDG ON RWY 27L. WE WERE GIVEN CLRNC FOR TURN TO 140 DEGS; CLRED FOR TKOF; TFC (Y) 3 MI FINAL. I LOOKED ON FINAL SAW THE ACFT AND THOUGHT TO MYSELF IT LOOKS FAIRLY CLOSE; BUT WITH INFO THAT LNDG ACFT FOR RWY 27L BEING OUT 3 MI AND LACK OF ACCURATE PERCEPTION OF DISTANCE OF ACFT ON FINAL; JUDGING ONLY FROM THEIR LNDG LIGHTS; I INITIATED THE MOVEMENT OF OUR ACFT; FROM THE HOLDING POINT TOWARDS TKOF. DUE TO THE LIGHTNESS OF OUR ACFT AND THE FACT THAT I BELIEVED IT WAS A SHORT 3 MI TWR HAD RPTED THE LNDG TFC WAS FROM LNDG; I ACCELERATED QUICKER THAN NORMAL. IT BECAME EVIDENT THAT THE LNDG TFC WAS MUCH CLOSER THAN 3 MI BUT BY THIS POINT I WAS COMMITTED (BEING DIRECTLY BELOW ITS FLT PATH). I ACCELERATED MUCH QUICKER NOW TO ASSURE THAT WE GOT OUT OF LNDG TFC'S FLT PATH AS QUICKLY AS WE COULD. LNDG TFC STATED THEY WERE GOING AROUND. TWR SAID THEY COULD CONTINUE AND LAND IF THEY WISHED. THE REGIONAL CARRIER IN FACT LANDED. I BELIEVE THE ACFT Y WAS IN FACT DUCKING UNDER TO LAND ON THE FIRST BRICK FOR AN EARLY TURN OFF TO THE TERMINAL BECAUSE I BELIEVE OUR VERT SEPARATION SHOULD HAVE BEEN MUCH MORE. I ALSO NOW BELIEVE THAT TWR BELIEVED ACFT Y HAD ALREADY LANDED BECAUSE THERE WAS ANOTHER ACFT ON FINAL; IT WAS PROBABLY 3 MI OUT.