HDG TRACK DEV CREATES A POTENTIAL CONFLICT. TCASII TA ALERTS FLC TO POSSIBLE FLC DEV IN THE CLRNC INTERP.

Narrative

WHILE DSNDING INTO SYR; ACFT HDG APPROX 105 DEGS; ZOB ISSUED WHAT I THOUGHT WAS A '15 DEG R' HDG FOR A VECTOR IN OUR DSCNT TO 1000 FT. I MUST HAVE MISUNDERSTOOD THE VECTOR AND TURNED R TO 120 DEGS. PASSING THROUGH 11300 FT. AT THE SAME TIME ZOB CALLED ABOUT OUR HDG; A TA ALERT APPEARED ON OUR TCASII. THE TARGET WAS AT OUR 2 O'CLOCK; 3.5 NM; 500 FT ABOVE AND CLBING. IT PASSED OUR 3 O'CLOCK AT 3 NM; 900 FT. ABOVE AND CLBING. I IMMEDIATELY TURNED L TO 090 DEGS; AFTER THE TARGET PASSED; AND ASKED MY COPLT WHAT HDG WAS ASSIGNED. HE FELT THE VECTOR WAS '15 DEGS L' AND HAD SET THAT ON HIS HDG BUG; AFTER READING BACK THE CLRNC. HE MISSED MY TURN TO R; BECAUSE HE WAS STARTING TO SET UP HIS RADIOS FOR THE APCH PLATES. I HAVE TO ASSUME THE MISTAKE WAS MINE IN MAKING THE TURN IN THE WRONG DIRECTION. HOWEVER; I WOULD HAVE SWORN I HEARD 'TURN R 15 DEGS.' THIS PROBLEM APPEARS TO BE A CLASSIC COM BREAKDOWN. THE CTR NEVER DID INFORM US OF THE NATURE OF THE VECTOR OR ISSUE ANY TFC; THAT MIGHT HAVE HELPED ME TO CATCH MY OWN MISTAKE.