Narrative:

A MD83 was a departure. I had pre-coordinated with feeder east to utilize their airspace to 'shortcut' departures and expedite them on course. I turned the MD83 early on course for his RNAV-SID; observed arrival traffic above him at 11;000; which was a B757. I thought I had the required four miles behind the B757 and then climbed the MD83 to 17;000. Apparently following a 'tarp' audit the computer readout showed that the MD83 was 3.96 miles behind; and 900 ft below the B757. Missing the required separation by .04 one hundredths of a mile and 100 ft vertically. Also after reviewing the playback when the MD83 checked in on my frequency on departure he stated his leaving altitude 100 ft higher than what his mode-C readout showed; which I believe may have actually provide the required 1;000 ft vertical separation when he passed behind the B757. However this was not pursued by our quality assurance department. Recommendation; please provide the same technology to the controller that exist to the quality assurance department. When you review these wake turbulence events there is a depiction on the playback that shows you where the wake terminates. We need this same depiction on the controller's radar scopes while working real time aircraft. It would be great if the above mentioned depiction would come up when in the vicinity of a heavy and; or B757 aircraft. Also give the controller the option to inhibit this tool if they want; but at least have it available for those that want to use it; aside from that; wait longer before turning and or climbing behind a heavy and or B757.

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Original NASA ASRS Text

Title: TRACON Controller described a loss of separation event that was identified by TARP; noting separation was lost by .04 miles and possibly 100 feet; suggesting better spacing tools be provided to controllers.

Narrative: A MD83 was a departure. I had pre-coordinated with Feeder East to utilize their airspace to 'shortcut' departures and expedite them on course. I turned the MD83 early on course for his RNAV-SID; observed arrival traffic above him at 11;000; which was a B757. I thought I had the required four miles behind the B757 and then climbed the MD83 to 17;000. Apparently following a 'TARP' audit the computer readout showed that the MD83 was 3.96 miles behind; and 900 FT below the B757. Missing the required separation by .04 one hundredths of a mile and 100 FT vertically. Also after reviewing the playback when the MD83 checked in on my frequency on Departure he stated his leaving altitude 100 FT higher than what his Mode-C readout showed; which I believe may have actually provide the required 1;000 FT vertical separation when he passed behind the B757. However this was not pursued by our Quality Assurance Department. Recommendation; please provide the same technology to the Controller that exist to the Quality Assurance Department. When you review these wake turbulence events there is a depiction on the playback that shows you where the wake terminates. We need this same depiction on the Controller's RADAR scopes while working real time aircraft. It would be great if the above mentioned depiction would come up when in the vicinity of a heavy and; or B757 aircraft. Also give the Controller the option to inhibit this tool if they want; but at least have it available for those that want to use it; aside from that; wait longer before turning and or climbing behind a heavy and or B757.

Data retrieved from NASA's ASRS site as of April 2012 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.