ACR X SAME ALT ASSIGNED. EVASIVE ACTION TURN. HAD LTSS FROM ACR Y. SYS ERROR. POTENTIAL CONFLICT.

Narrative

DEN CTR CTLR HAD GIVEN ACR Y DIRECT DENVER DUE TO WX ALONG OUR NORMAL RTE (ARR GATE) TO DENVER. LEVEL AT 8000 FT; NOTICED AIR TFC HEAD-ON AND CLOSING FAST; TARGET STATIONARY AND INCREASING IN SIZE. TURNED L TO AVOID TFC. EVEN THOUGH WE WERE ON IFR FLT PLAN; DSCNT WAS IN GOOD VFR AND WE AVOIDED TFC EASILY. AS TFC APCHED OUR 1:30 POS; CTLR; WHO WAS CHARACTERISTICALLY SILENT; SUDDENLY SAID 'ACR X; IMMEDIATE R TURN 90 DEGS.' OF COURSE; WE COULD NOT EXECUTE THIS AS THIS WOULD HAVE PUT US ON COLLISION COURSE WITH THE ACR Y. WE DISREGARDED THE CTLR'S INSTRUCTIONS AND WITHIN A SECOND HE SAID 'IMMEDIATE L TURN 90 DEGS;' BY NOW ACR HAD PASSED WELL BEHIND US AND WAS OBVIOUSLY NOT A FACTOR. WE TOLD THE CTLR WE HAD ACR IN SIGHT AND THAT HE WAS NOW AT OUR 5 O'CLOCK POS; NO FACTOR. HE THEN HANDED US OFF TO DENVER APCH. FACTORS CAUSING THE INCIDENT: 1) UNUSUAL ROUTING TO DENVER. CTLR WAS BUSY WITH MANY DIVERTING ACFT; BUT WE WERE THE ONLY ONE HE HAD CLRED DIRECT. 2) WE SHOULD HAVE BEEN STEERED FARTHER AWAY FROM THE MLG AS WE WERE STILL IN CTR AIRSPACE AND SHOULD HAVE HAD 5 MI HORIZ SEPARATION. 3) WE SHOULD HAVE ASKED CTLR ABOUT SWITCHING TO DEN APCH. 4) SHOULD HAVE TOLD CTLR WE HAD TFC UPON FIRST CONTACT.