POTENTIAL CONFLICT LTSS DURING RADAR VECTORING. OPERROR.

Narrative

DUE TO WX AT IAH ARPT ARRIVING ACFT WERE BEING VECTORED FOR SPACING ON THE ARR (COUGAR 5 TO IAH). WE WERE GIVEN A HDG (APPROX 100 DEGS) TO INTERCEPT THE IAH 305 DEG RADIAL FOR THE COUGAR 5 ARR. WE WERE ASSIGNED AN ALT OF FL280. PRIOR TO REACHING THE 305 DEG RADIAL WE WERE TOLD TO MAINTAIN HDG FOR VECTORING. AFTER PASSING THROUGH THE 305 DEG RADIAL WE WERE TOLD TO TURN R TO A HDG OF 220 DEGS AND DSND TO FL260. AS WE APCHED THE 305 DEG RADIAL FOR THE SECOND TIME AND DSNDING THROUGH ABOUT FL265; WE RECEIVED A TA ON THE TCASII SHOWING AN INTRUDER AT OUR 12 O'CLOCK POS 300 FT BELOW US. THE NEXT SERIES OF EVENTS HAPPENED IN RAPID SUCCESSION. ATC TOLD US TO CLB TO FL280; THE CAPT INITIATED AN IMMEDIATE CLB; AND THE TCASII ISSUED AN RA TO CLB; CLB. AS WE CLBED THE CONFLICT WAS RESOLVED. AFTER LEVELING AT FL280 WE WERE TOLD TO TURN R TO A HDG OF 100 DEGS. ON THAT HDG WE WERE TO INTERCEPT THE IAH 305 DEG RADIAL; CLRED FOR THE COUGAR 5 ARR AND CROSS HOGIE AT 10000 FT. THE REMAINDER OF THE FLT WAS UNEVENTFUL. AS I SAID EARLIER THE TA INDICATED TFC 300 FT BELOW US; BUT I'M NOT SURE OF THE LATERAL DISTANCE SINCE I DON'T RECALL THE SCALE THE TCASII WAS SET TO. IT SHOULD BE NOTED THAT THE CTLR WHO TOLD US TO CLB BACK TO FL280 WAS NOT THE SAME CTLR AS THE CTLR WHO HAD BEEN VECTORING US (TURN HDG 220 DEGS; DSND TO FL260). I DO NOT KNOW IF THERE WAS A CTLR CHANGE IN PROGRESS OR IF A SUPVR TOOK OVER WHEN THE CONFLICT WAS NOTED.