Narrative:

We were cruising our mdt level at 11000', full passenger load (37), and tracking into csg on the 195 degree right. ZTL had turned us over to csg approach and at about 10 NM south of the VOR he turned us directly east (090 degree heading) for traffic spacing into atl. After heading east about 1 min csg approach told us to 'descend immediately to 10000', traffic conflict,' and turned us to a north heading. Of course we complied and scanned for traffic, but saw nothing. We then inquired about traffic position. Later in atl operations, I was talking to another pilot who had just flown in from aby on flight yxb (our flight was byb). He was also inbound to csg at 11000'. He said he was looking into the sunset and saw our lights and was trying to determine our direction. He then saw us go by just after we started our immediate descent and felt our wake turbulence. It seems quite clear that the csg approach controller had fixated on traffic spacing and vectored us into a conflict situation west/O first scanning for other traffic. He caught his own mistake but (fortunately) just in time. Descending and turning north put our high wing aircraft in a position where we could not see anything. He was above and somewhat behind us. The light transport crew had a contributing factor of looking into the sunset. The see and avoid concept has significant limitations even west/O these handicaps. Even a dozen pairs of eyes can't see in all directions all the time. The fact that I had flown about 6 1/2 hours that day should not be considered a contributing factor. When ATC says, 'descend immediately,' they get my attention.

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Original NASA ASRS Text

Title: NMAC ACR-MDT AND ACR-LTT BOTH IFR. OPERATIONAL ERROR.

Narrative: WE WERE CRUISING OUR MDT LEVEL AT 11000', FULL PAX LOAD (37), AND TRACKING INTO CSG ON THE 195 DEG R. ZTL HAD TURNED US OVER TO CSG APCH AND AT ABOUT 10 NM S OF THE VOR HE TURNED US DIRECTLY E (090 DEG HDG) FOR TFC SPACING INTO ATL. AFTER HDG E ABOUT 1 MIN CSG APCH TOLD US TO 'DSND IMMEDIATELY TO 10000', TFC CONFLICT,' AND TURNED US TO A N HDG. OF COURSE WE COMPLIED AND SCANNED FOR TFC, BUT SAW NOTHING. WE THEN INQUIRED ABOUT TFC POS. LATER IN ATL OPS, I WAS TALKING TO ANOTHER PLT WHO HAD JUST FLOWN IN FROM ABY ON FLT YXB (OUR FLT WAS BYB). HE WAS ALSO INBND TO CSG AT 11000'. HE SAID HE WAS LOOKING INTO THE SUNSET AND SAW OUR LIGHTS AND WAS TRYING TO DETERMINE OUR DIRECTION. HE THEN SAW US GO BY JUST AFTER WE STARTED OUR IMMEDIATE DSCNT AND FELT OUR WAKE TURB. IT SEEMS QUITE CLEAR THAT THE CSG APCH CTLR HAD FIXATED ON TFC SPACING AND VECTORED US INTO A CONFLICT SITUATION W/O FIRST SCANNING FOR OTHER TFC. HE CAUGHT HIS OWN MISTAKE BUT (FORTUNATELY) JUST IN TIME. DSNDING AND TURNING N PUT OUR HIGH WING ACFT IN A POS WHERE WE COULD NOT SEE ANYTHING. HE WAS ABOVE AND SOMEWHAT BEHIND US. THE LTT CREW HAD A CONTRIBUTING FACTOR OF LOOKING INTO THE SUNSET. THE SEE AND AVOID CONCEPT HAS SIGNIFICANT LIMITATIONS EVEN W/O THESE HANDICAPS. EVEN A DOZEN PAIRS OF EYES CAN'T SEE IN ALL DIRECTIONS ALL THE TIME. THE FACT THAT I HAD FLOWN ABOUT 6 1/2 HRS THAT DAY SHOULD NOT BE CONSIDERED A CONTRIBUTING FACTOR. WHEN ATC SAYS, 'DSND IMMEDIATELY,' THEY GET MY ATTN.

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.