Narrative:

We were on an assigned heading and altitude of 050 degree and 3500', approximately 7 mi southeast of gso airport on an IFR flight plan and VFR conditions. Approach control advised me of traffic at 1 O'clock at 3500', an small aircraft an 4 mi (VFR), that had us in sight. I requested a vector around traffic and the controller repeated that the traffic had us in sight and would maintain visual separation. We again looked out and I spotted him at 12 O'clock, 3500', on the same heading as us, 050 degree, and less than 1 mi. I felt he must be looking at the wrong traffic as he could not see us if we were right on his tail! Not knowing if he might turn left or right as we passed him at a 100 KT overtake, I told the first officer to advise approach we were leaving 3500' to avoid hitting him. We were given a clearance immediately to 2500' as we passed through 3300'. We missed the aircraft approximately 700-800' below and 100' horizontal. We were then cleared for a visual approach and I reprimanded the controller for not vectoring us around the traffic as we requested. He asked if we wished to file a complaint and I said 'just forget it' as we were now on a left base for 23 and cleared for a visual approach. We needed to devote our time to landing the airplane at this point. Upon landing I was advised to call tower and the supervisor informed me the controller reported us for leaving our assigned altitude. After talking to the supervisor he said he felt I took the appropriate action, but to call him after he listened to the tape. I feel this could have been totally avoided if he had just vectored us around the VFR aircraft as requested. We were 100 KT faster and we could easily have been vectored around him instead of him trying to dodge us (I personally feel he never saw us).

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Original NASA ASRS Text

Title: LGT FLT CREW REQUESTED VECTORS AROUND TRAFFIC THEY WERE OVERTAKING WHICH 'HAD THEM IN SIGHT'. ATC DENIED VECTORS, CREW ALERTED ALT AS EVASIVE ACTION.

Narrative: WE WERE ON AN ASSIGNED HDG AND ALT OF 050 DEG AND 3500', APPROX 7 MI SE OF GSO ARPT ON AN IFR FLT PLAN AND VFR CONDITIONS. APCH CTL ADVISED ME OF TFC AT 1 O'CLOCK AT 3500', AN SMA AN 4 MI (VFR), THAT HAD US IN SIGHT. I REQUESTED A VECTOR AROUND TFC AND THE CTLR REPEATED THAT THE TFC HAD US IN SIGHT AND WOULD MAINTAIN VISUAL SEPARATION. WE AGAIN LOOKED OUT AND I SPOTTED HIM AT 12 O'CLOCK, 3500', ON THE SAME HDG AS US, 050 DEG, AND LESS THAN 1 MI. I FELT HE MUST BE LOOKING AT THE WRONG TFC AS HE COULD NOT SEE US IF WE WERE RIGHT ON HIS TAIL! NOT KNOWING IF HE MIGHT TURN LEFT OR RIGHT AS WE PASSED HIM AT A 100 KT OVERTAKE, I TOLD THE F/O TO ADVISE APCH WE WERE LEAVING 3500' TO AVOID HITTING HIM. WE WERE GIVEN A CLRNC IMMEDIATELY TO 2500' AS WE PASSED THROUGH 3300'. WE MISSED THE ACFT APPROX 700-800' BELOW AND 100' HORIZ. WE WERE THEN CLRED FOR A VISUAL APCH AND I REPRIMANDED THE CTLR FOR NOT VECTORING US AROUND THE TFC AS WE REQUESTED. HE ASKED IF WE WISHED TO FILE A COMPLAINT AND I SAID 'JUST FORGET IT' AS WE WERE NOW ON A LEFT BASE FOR 23 AND CLRED FOR A VISUAL APCH. WE NEEDED TO DEVOTE OUR TIME TO LNDG THE AIRPLANE AT THIS POINT. UPON LNDG I WAS ADVISED TO CALL TWR AND THE SUPVR INFORMED ME THE CTLR REPORTED US FOR LEAVING OUR ASSIGNED ALT. AFTER TALKING TO THE SUPVR HE SAID HE FELT I TOOK THE APPROPRIATE ACTION, BUT TO CALL HIM AFTER HE LISTENED TO THE TAPE. I FEEL THIS COULD HAVE BEEN TOTALLY AVOIDED IF HE HAD JUST VECTORED US AROUND THE VFR ACFT AS REQUESTED. WE WERE 100 KT FASTER AND WE COULD EASILY HAVE BEEN VECTORED AROUND HIM INSTEAD OF HIM TRYING TO DODGE US (I PERSONALLY FEEL HE NEVER SAW US).

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.