A80 approach controller experienced possible loss of separation.

Attributes
ACN	590883
Time
Date	200308
Day	Wed
Local Time Of Day	0601 To 1200
Place
State Reference	GA
Altitude	msl single value : 5000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : a80.tracon
Operator	general aviation : personal
Make Model Name	PC-12
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : a80.tracon
Operator	general aviation : personal
Make Model Name	Bonanza 36
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller radar : 12 controller supervisory : 9 controller time certified in position1 : 4
ASRS Report	590883
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert other controllera
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

Pc-12 on downwind to runway 20L at pdk at 5000 ft. BE36 on vector to ryy at 5000 ft. There were other aircraft in the immediate area which caused data tag overlap. I had already switched the BE36 to another frequency. The aircraft were in potential conflict, so I issued immediate descent to 4000 ft to the pc-12 and issued traffic 2 O'clock position, 5 mi at 5000 ft. The other controller issued a northwest heading to the BE36 and I then issued a right turn to 090 degrees on the pc-12 to obtain divergence. The data tag overlap contributed to the situation, plus the BE36 came over at 5000 ft wbound and I left him there instead of going to 4000 ft or 6000 ft which would have been correct for direction of flight.

Original NASA ASRS Text

Title: A80 APCH CTLR EXPERIENCED POSSIBLE LOSS OF SEPARATION.

Narrative: PC-12 ON DOWNWIND TO RWY 20L AT PDK AT 5000 FT. BE36 ON VECTOR TO RYY AT 5000 FT. THERE WERE OTHER ACFT IN THE IMMEDIATE AREA WHICH CAUSED DATA TAG OVERLAP. I HAD ALREADY SWITCHED THE BE36 TO ANOTHER FREQ. THE ACFT WERE IN POTENTIAL CONFLICT, SO I ISSUED IMMEDIATE DSCNT TO 4000 FT TO THE PC-12 AND ISSUED TFC 2 O'CLOCK POS, 5 MI AT 5000 FT. THE OTHER CTLR ISSUED A NW HEADING TO THE BE36 AND I THEN ISSUED A R TURN TO 090 DEGS ON THE PC-12 TO OBTAIN DIVERGENCE. THE DATA TAG OVERLAP CONTRIBUTED TO THE SIT, PLUS THE BE36 CAME OVER AT 5000 FT WBOUND AND I LEFT HIM THERE INSTEAD OF GOING TO 4000 FT OR 6000 FT WHICH WOULD HAVE BEEN CORRECT FOR DIRECTION OF FLT.

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.