Narrative:

I was working west arrival. Aircraft X checked in on my frequency on the gqe 3 arrival at 10000 ft. I issued aircraft X a 110 degree heading and descended them to 6000 ft for runway 18R ILS approach. As aircraft X was passing gqe; I noticed the collision alert going off. I looked and there was traffic for aircraft X at his 10 O'clock position and 2 mi at 8500 ft. I issued the traffic and a turn to a 180 degree heading if they wanted. Aircraft X replied that they were climbing for an RA from their TCAS. By this time; I advised aircraft X that they were clear of the traffic and when they felt ready; they could descend back to 6000 ft. A company aircraft in trail of aircraft X reported that the aircraft appeared to be a low wing; single engine aircraft and the indicated altitude appeared close to correct. I believe there were several reasons why I was late issuing a traffic call. First; we were in between pushes with light traffic; therefore; my scan was lulled somewhat. Second; at the west arrival position; there is glare from a wall of monitors behind the position that can make it difficult to see. Finally; mem has stars which allows for different colors for different priorities of data tags. Unidented VFR tags are green and idented VFR tags and IFR tags associated with the position I am working are white and points are amber. The unidented VFR tag was green; and controllers have a tendency to put green tags out of their focus of attention. The collision alert worked perfectly in this instance (it is notorious for going off after aircraft have passed); so I was able to give a timely traffic alert.

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Original NASA ASRS Text

Title: MEM APCH CTLR DESCRIBED CONFLICT EVENT AT 8500 BETWEEN VFR AND MEM ARR CITING LATE ISSUANCE OF TFC AND LISTING EQUIP ANOMALIES AS CONTRIBUTORY.

Narrative: I WAS WORKING W ARR. ACFT X CHKED IN ON MY FREQ ON THE GQE 3 ARR AT 10000 FT. I ISSUED ACFT X A 110 DEG HDG AND DSNDED THEM TO 6000 FT FOR RWY 18R ILS APCH. AS ACFT X WAS PASSING GQE; I NOTICED THE COLLISION ALERT GOING OFF. I LOOKED AND THERE WAS TFC FOR ACFT X AT HIS 10 O'CLOCK POS AND 2 MI AT 8500 FT. I ISSUED THE TFC AND A TURN TO A 180 DEG HDG IF THEY WANTED. ACFT X REPLIED THAT THEY WERE CLBING FOR AN RA FROM THEIR TCAS. BY THIS TIME; I ADVISED ACFT X THAT THEY WERE CLR OF THE TFC AND WHEN THEY FELT READY; THEY COULD DSND BACK TO 6000 FT. A COMPANY ACFT IN TRAIL OF ACFT X RPTED THAT THE ACFT APPEARED TO BE A LOW WING; SINGLE ENG ACFT AND THE INDICATED ALT APPEARED CLOSE TO CORRECT. I BELIEVE THERE WERE SEVERAL REASONS WHY I WAS LATE ISSUING A TFC CALL. FIRST; WE WERE IN BTWN PUSHES WITH LIGHT TFC; THEREFORE; MY SCAN WAS LULLED SOMEWHAT. SECOND; AT THE W ARR POS; THERE IS GLARE FROM A WALL OF MONITORS BEHIND THE POS THAT CAN MAKE IT DIFFICULT TO SEE. FINALLY; MEM HAS STARS WHICH ALLOWS FOR DIFFERENT COLORS FOR DIFFERENT PRIORITIES OF DATA TAGS. UNIDENTED VFR TAGS ARE GREEN AND IDENTED VFR TAGS AND IFR TAGS ASSOCIATED WITH THE POS I AM WORKING ARE WHITE AND POINTS ARE AMBER. THE UNIDENTED VFR TAG WAS GREEN; AND CTLRS HAVE A TENDENCY TO PUT GREEN TAGS OUT OF THEIR FOCUS OF ATTN. THE COLLISION ALERT WORKED PERFECTLY IN THIS INSTANCE (IT IS NOTORIOUS FOR GOING OFF AFTER ACFT HAVE PASSED); SO I WAS ABLE TO GIVE A TIMELY TFC ALERT.

Data retrieved from NASA's ASRS site as of May 2009 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.