Narrative:

Controller 'a' working a sector southeast of mine, radar idented a VFR small aircraft X at 9500 ft. The small aircraft X was landing in my area so I took radar handoff. Controller 'a' then called and said the small aircraft X was now IFR descending to 3000 ft on a 320 degree heading. I approved. Aircraft came over to my frequency. Aircraft transitioned through controller 'B' airspace. My aircraft descending out of 6000 ft now still on 320 degree heading. Controller 'B' aircraft, an light transport jet, at 6000 ft, sbound, descending on convergent course with my small aircraft X. I call and alert controller 'B' to situation. Both aircraft at 5000 ft now descending, converging, 5 mi apart. Light transport is descending faster than small aircraft X so I climb small aircraft X from 4700 ft back to 5000 ft. Light transport is below small aircraft X but then also begins to climb (controller 'B' had same idea as me and climbed light transport back to 5000 ft). Targets pass, light transport is below, minimum separation is 200 ft, 1/2 mi. My small aircraft X does not see light transport until moment they pass. Cause of problem: either controller 'a' did not point out small aircraft X to controller 'B' or controller 'a' did point out and controller 'B' approved without really understanding situation. Contributing factor: small aircraft X was left on a VFR beacon code after having been given IFR clearance. If small aircraft X was on IFR code, controller 'B' might have been more aware of and attentive to small aircraft X. Controller 'B' and I were unaware of each other's intentions. We both stopped our descending aircraft and both climbed to 5000 ft. When I called and brought situation to controller 'B's' attention I did not ask his intentions or tell him mine -- if we knew what kind of action one of us was planning to take, situation may have been avoided.

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Original NASA ASRS Text

Title: SMA X HAD LTSS FROM LTT SAME ALT ASSIGNED. SYS ERROR. EVASIVE ACTION TAKEN.

Narrative: CTLR 'A' WORKING A SECTOR SE OF MINE, RADAR IDENTED A VFR SMA X AT 9500 FT. THE SMA X WAS LNDG IN MY AREA SO I TOOK RADAR HDOF. CTLR 'A' THEN CALLED AND SAID THE SMA X WAS NOW IFR DSNDING TO 3000 FT ON A 320 DEG HDG. I APPROVED. ACFT CAME OVER TO MY FREQ. ACFT TRANSITIONED THROUGH CTLR 'B' AIRSPACE. MY ACFT DSNDING OUT OF 6000 FT NOW STILL ON 320 DEG HDG. CTLR 'B' ACFT, AN LTT JET, AT 6000 FT, SBOUND, DSNDING ON CONVERGENT COURSE WITH MY SMA X. I CALL AND ALERT CTLR 'B' TO SIT. BOTH ACFT AT 5000 FT NOW DSNDING, CONVERGING, 5 MI APART. LTT IS DSNDING FASTER THAN SMA X SO I CLB SMA X FROM 4700 FT BACK TO 5000 FT. LTT IS BELOW SMA X BUT THEN ALSO BEGINS TO CLB (CTLR 'B' HAD SAME IDEA AS ME AND CLBED LTT BACK TO 5000 FT). TARGETS PASS, LTT IS BELOW, MINIMUM SEPARATION IS 200 FT, 1/2 MI. MY SMA X DOES NOT SEE LTT UNTIL MOMENT THEY PASS. CAUSE OF PROB: EITHER CTLR 'A' DID NOT POINT OUT SMA X TO CTLR 'B' OR CTLR 'A' DID POINT OUT AND CTLR 'B' APPROVED WITHOUT REALLY UNDERSTANDING SIT. CONTRIBUTING FACTOR: SMA X WAS LEFT ON A VFR BEACON CODE AFTER HAVING BEEN GIVEN IFR CLRNC. IF SMA X WAS ON IFR CODE, CTLR 'B' MIGHT HAVE BEEN MORE AWARE OF AND ATTENTIVE TO SMA X. CTLR 'B' AND I WERE UNAWARE OF EACH OTHER'S INTENTIONS. WE BOTH STOPPED OUR DSNDING ACFT AND BOTH CLBED TO 5000 FT. WHEN I CALLED AND BROUGHT SIT TO CTLR 'B'S' ATTN I DID NOT ASK HIS INTENTIONS OR TELL HIM MINE -- IF WE KNEW WHAT KIND OF ACTION ONE OF US WAS PLANNING TO TAKE, SIT MAY HAVE BEEN AVOIDED.

Data retrieved from NASA's ASRS site as of July 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.