Narrative:

Prior to the incident; a scattered layer was lingering on final for runway 04R and runway 10. VMC prevailed at the time. I had notified my flm that visual separation from the marker could not be guaranteed. Planes were visible outside of 10 miles but they would disappear around 6 miles and reappear about 3 miles from the runway. An E145 was crossing the outer marker for runway 4R. I used a j-ring and determined that separation existed but would not continue. The E145 was a little over 2.5 miles from the preceding arrival with an overtake of 50 KTS. When the E145 failed to contact me at the marker I made a call to ensure they were with me. Once two-way radio communication had been established; I immediately issued go around instructions to the E145 to continue tracking the localizer and maintain 4;000 ft. Upon coordination with the other controllers my only course of action was to turn the E145 to the north; overfly my runway 10 arrivals and get him on a 320 heading. There was a dc-10 just northeast of the field after departing runway 32L in a right turn to a 140 heading; typically missed approaches on this configuration depart the airspace on the 140 heading. Once I was told about the traffic I was missing I turned the E145 north and stopped his climb at 3;000 ft because the dc-10 was climbing out of 3;000 ft for 5;000 ft. The E145 made his turn at around a 3 mile final for runway 04R and was well insight prior to that. The dc-10 was in sight as well flying southeast bound. Wake turbulence was never a factor because the flight paths of the two aircraft never intersected. Upon reviewing the radar data; the E145 and the dc-10 got within a little over two miles of each other because the E145 had to turn inside of the dc-10. The event was reviewed and unofficially we all determined I had no other course of action to take. If I had gone southeast with him; we would have had a wake turbulence issue. I; the inbound ground controller and the supervisor on duty all reported that both aircraft were insight at all times. The planes had already diverged when the dc-10 disappeared into the overcast layer. Recommendation; there really isn't anything to prevent this type of thing from occurring. The weather played a factor but visual separation was applied until the aircraft were no longer a factor. Plan X at ord can be dicey in the event of a missed approach. In most circumstances a missed approach can get in trail with a southbound departure and depart the bravo on a 140 heading. This wasn't an option in this case. Had we not been able to apply visual separation here these circumstances would be a lot different. The dc-10 was hugging the 140 heading about 1 mile east of the field and I didn't feel safe turning the E145 immediately on the go around as the runway 10 finals were tight and we may have had another go around. The radar data and tapes were investigated prior to me being relieved. No one had notified quality assurance that I had been maintaining visual separation at all times with the missed approach and the dc-10. The investigation was to determine if a loss of separation had existed with the E145 and the preceding aircraft but the tapes and radar data determined that I initiated a go around immediately after acquiring two way radio communications and that separation hadn't been lost as of then. I believe the separation at the time of the go around was 2.58 diminishing rapidly due to the 50 KT overtake. This was simply a case of separation would not continue to exist and that I had no other options other then to initially point the E145 at the dc-10.

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Original NASA ASRS Text

Title: ORD Controller described an ATC directed go-around event because of an over take situation that resulted in an ATC applied visual separation with other departure traffic.

Narrative: Prior to the incident; a scattered layer was lingering on final for Runway 04R and Runway 10. VMC prevailed at the time. I had notified my FLM that visual separation from the marker could not be guaranteed. Planes were visible outside of 10 miles but they would disappear around 6 miles and reappear about 3 miles from the runway. An E145 was crossing the outer marker for Runway 4R. I used a J-ring and determined that separation existed but would not continue. The E145 was a little over 2.5 miles from the preceding arrival with an overtake of 50 KTS. When the E145 failed to contact me at the marker I made a call to ensure they were with me. Once two-way radio communication had been established; I immediately issued go around instructions to the E145 to continue tracking the localizer and maintain 4;000 FT. Upon coordination with the other controllers my only course of action was to turn the E145 to the north; overfly my Runway 10 arrivals and get him on a 320 heading. There was a DC-10 just northeast of the field after departing Runway 32L in a right turn to a 140 heading; typically missed approaches on this configuration depart the airspace on the 140 heading. Once I was told about the traffic I was missing I turned the E145 north and stopped his climb at 3;000 FT because the DC-10 was climbing out of 3;000 FT for 5;000 FT. The E145 made his turn at around a 3 mile final for Runway 04R and was well insight prior to that. The DC-10 was in sight as well flying southeast bound. Wake turbulence was never a factor because the flight paths of the two aircraft never intersected. Upon reviewing the RADAR data; the E145 and the DC-10 got within a little over two miles of each other because the E145 had to turn inside of the DC-10. The event was reviewed and unofficially we all determined I had no other course of action to take. If I had gone southeast with him; we would have had a wake turbulence issue. I; the inbound Ground Controller and the Supervisor On Duty all reported that both aircraft were insight at all times. The planes had already diverged when the DC-10 disappeared into the overcast layer. Recommendation; there really isn't anything to prevent this type of thing from occurring. The weather played a factor but visual separation was applied until the aircraft were no longer a factor. Plan X at ORD can be dicey in the event of a missed approach. In most circumstances a missed approach can get in trail with a southbound departure and depart the Bravo on a 140 heading. This wasn't an option in this case. Had we not been able to apply visual separation here these circumstances would be a lot different. The DC-10 was hugging the 140 heading about 1 mile east of the field and I didn't feel safe turning the E145 immediately on the go around as the Runway 10 finals were tight and we may have had another go around. The RADAR data and tapes were investigated prior to me being relieved. No one had notified Quality Assurance that I had been maintaining visual separation at all times with the missed approach and the DC-10. The investigation was to determine if a loss of separation had existed with the E145 and the preceding aircraft but the tapes and RADAR data determined that I initiated a go around immediately after acquiring two way radio communications and that separation hadn't been lost as of then. I believe the separation at the time of the go around was 2.58 diminishing rapidly due to the 50 KT overtake. This was simply a case of separation would not continue to exist and that I had no other options other then to initially point the E145 at the DC-10.

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.