Narrative:

I was working the arrival local for runway 26L during simultaneous approaches on 26R with the weather gradually improving from a low deck and visibility. It all started when aircraft X told me he was going around. After repeated attempts to find out why; I asked if there was some sort of emergency and they said no; but could we call their company and have a tow truck standing by in case they needed it to get off the runway for they had a steering issue. Of course; I notified everyone; handed him back to approach and he was gone for quite awhile. When he came back in I was told he had resolved the issue so they didn't call out the rescue trucks. About the same place on final; aircraft X said they once again had the same steering issue but they were going to land and asked something about turn-offs. I told the pilot any turn-off was available and notifying the flm to call out the trucks. The aircraft landed and turned off at the last high speed without incident but said they needed to sit there for five minutes to go through checklists and no assistance was required. The trucks then got to the runway and asked where the aircraft was and I told them what happened and to hold short of the runway. Since everything seemed finished I let two carriers land since the finals were full and they were 5 miles in trail of aircraft X. The airport vehicle called me asking were the aircraft was so I told him also. I then started to give a briefing to my relief. Airport operations vehicle called me again at the approach end wanting to inspect the runway but I told him I couldn't because of the aircraft on final and the critical area needed protection. He then closed the runway on me which started the next ordeal. I canceled the approach and landing clearances of the next two aircraft on final; aircraft Y and aircraft Z; turned off the aircraft Y that was on the runway; put the airport vehicle on the runway; co-ordinated with the departure local to miss his northbound coa all while aircraft were checking in; the final monitor was breaking people out; and the emergency trucks were calling. I turned aircraft Y south then southeast then the airport vehicle called and said the runway was open. I looked at the aircraft Z but he was too close to rejoin the approach so I turned him south to fall in behind the aircraft Y then climbed the aircraft Y and turned him east for the downwind. I then called the final to co-ordinate all this. When I looked at the aircraft Z again he seemed to be tracking more of a south-southeasterly heading and catching the aircraft Y so I verified his heading then had to vector him further south then northeast then east to get in trail of the aircraft Y. I then climbed and shipped him to final. The next day I was notified that I had a category C error for there was a ten second period when I didn't have diverging courses and only had 80.33% separation. They showed me the track where the aircraft Z turned on a dime south and had cut the corner with aircraft Y whereas I had thought I was behind him the whole time. This problem could have been avoided if I had followed my gut feeling that the aircraft X was going to be an emergency again; and had insisted that the trucks be waiting and the final cleared behind in case the runway couldn't be cleared timely. Even then; if someone had to go around; I would have had more time to think; and had less adrenaline flowing; and may have given the aircraft Z the ten more degrees divergence he needed.

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Original NASA ASRS Text

Title: Local Controller described the confused events surrounding the handling of an emergency inbound aircraft; along with confused coordination with an Airport vehicle and multiple response instructions that led to a loss of separation.

Narrative: I was working the arrival Local for Runway 26L during simultaneous approaches on 26R with the weather gradually improving from a low deck and visibility. It all started when Aircraft X told me he was going around. After repeated attempts to find out why; I asked if there was some sort of emergency and they said no; but could we call their company and have a tow truck standing by in case they needed it to get off the runway for they had a steering issue. Of course; I notified everyone; handed him back to approach and he was gone for quite awhile. When he came back in I was told he had resolved the issue so they didn't call out the rescue trucks. About the same place on final; Aircraft X said they once again had the same steering issue but they were going to land and asked something about turn-offs. I told the pilot any turn-off was available and notifying the FLM to call out the trucks. The aircraft landed and turned off at the last high speed without incident but said they needed to sit there for five minutes to go through checklists and no assistance was required. The trucks then got to the runway and asked where the aircraft was and I told them what happened and to hold short of the runway. Since everything seemed finished I let two Carriers land since the finals were full and they were 5 miles in trail of Aircraft X. The airport vehicle called me asking were the aircraft was so I told him also. I then started to give a briefing to my relief. Airport Operations vehicle called me again at the approach end wanting to inspect the runway but I told him I couldn't because of the aircraft on final and the critical area needed protection. He then closed the runway on me which started the next ordeal. I canceled the approach and landing clearances of the next two aircraft on final; Aircraft Y and Aircraft Z; turned off the Aircraft Y that was on the runway; put the Airport vehicle on the runway; co-ordinated with the Departure Local to miss his Northbound COA all while aircraft were checking in; the final monitor was breaking people out; and the emergency trucks were calling. I turned Aircraft Y South then Southeast then the Airport vehicle called and said the runway was open. I looked at the Aircraft Z but he was too close to rejoin the approach so I turned him South to fall in behind the Aircraft Y then climbed the Aircraft Y and turned him East for the downwind. I then called the final to co-ordinate all this. When I looked at the Aircraft Z again he seemed to be tracking more of a South-Southeasterly heading and catching the Aircraft Y so I verified his heading then had to vector him further South then Northeast then East to get in trail of the Aircraft Y. I then climbed and shipped him to final. The next day I was notified that I had a Category C Error for there was a ten second period when I didn't have diverging courses and only had 80.33% separation. They showed me the track where the Aircraft Z turned on a dime South and had cut the corner with Aircraft Y whereas I had thought I was behind him the whole time. This problem could have been avoided if I had followed my gut feeling that the Aircraft X was going to be an emergency again; and had insisted that the trucks be waiting and the final cleared behind in case the runway couldn't be cleared timely. Even then; if someone had to go around; I would have had more time to think; and had less adrenaline flowing; and may have given the Aircraft Z the ten more degrees divergence he needed.

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.