Narrative:

I was working local control 1/local control 2 with high complexity due to construction closures and vehicles occasionally calling for clearances. Runway 11R and runway 2/20 were closed to allow painting to occur; so runway 11L was the single active runway for fixed wing aircraft. Traffic volume was increasing with multiple departures and aircraft inbound that were requesting pattern work to the single runway; with occasional helicopter operations. I remember that I had a mooney inbound on a left base to 11L; with other inbounds and at least two other aircraft in the pattern for 11L; including a skyhawk. There seemed to be multiple requests for additional services that I felt added to frequency congestion and made the situation more complex and frustrating at times. I honestly do not recall working this level of traffic in awhile to a single runway; so I was definitely 'rusty' for this operation. But I felt that I needed to take advantage of the situation to push some traffic to maintain my skills and controlling ability. I recall that my initial plan was to have another mooney depart prior to the second mooney arrival and communicated this to the arriving mooney before clearing him to land. I also advised the skyhawk to extend downwind to make room for the two departures; and that I would call his base turn. However; the skyhawk did not appear to continue downwind and instead turned base from a position that would not allow space for the departures; and could conflict with the mooney. When I told the skyhawk to turn out to the west and square his base (reminding him that I said I would tell him when to turn base); I believe I lost awareness of where the mooney was on final; and instead told a skylane of the position of the mooney upwind as I cleared him for take off without remembering that the mooney was so close in on final! I thought I had a hole for the departure; but I did not. I saw the inbound mooney short final and immediately issued a go around that was acknowledged by the pilot as he began a climb. After the skylane was established upwind; he acknowledged that he had the mooney ahead in sight. After the incident; I took steps to regain control of the pattern by restricting pattern work and holding aircraft outside class D until I was confident that I regained full awareness of my traffic situation. In hindsight; I needed to take steps earlier to gain greater control of the pattern as traffic was building. This event is a sobering learning experience about my own personal signs of overload developing; and I will apply these personal lessons learned in the future. The bottom line was my scan; my scan of strip bays and out the window broke down and I lost situational awareness of the position of the mooney on final. I fell behind the volume of traffic that was inbound to the airport at that time; and allowed a pilot's miscue (unplanned early base turn) distract me into inadvertently issuing a badly timed take off clearance.

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Original NASA ASRS Text

Title: Tower Controller described a very busy/complex traffic situation that resulted in a go around; the reporter noting multiple factors and distractors leading to the event.

Narrative: I was working Local Control 1/Local Control 2 with high complexity due to construction closures and vehicles occasionally calling for clearances. Runway 11R and Runway 2/20 were closed to allow painting to occur; so Runway 11L was the single active runway for fixed wing aircraft. Traffic volume was increasing with multiple departures and aircraft inbound that were requesting pattern work to the single runway; with occasional helicopter operations. I remember that I had a Mooney inbound on a left base to 11L; with other inbounds and at least two other aircraft in the pattern for 11L; including a Skyhawk. There seemed to be multiple requests for additional services that I felt added to frequency congestion and made the situation more complex and frustrating at times. I honestly do not recall working this level of traffic in awhile to a single runway; so I was definitely 'rusty' for this operation. But I felt that I needed to take advantage of the situation to push some traffic to maintain my skills and controlling ability. I recall that my initial plan was to have another Mooney depart prior to the second Mooney arrival and communicated this to the arriving Mooney before clearing him to land. I also advised the Skyhawk to extend downwind to make room for the two departures; and that I would call his base turn. However; the Skyhawk did not appear to continue downwind and instead turned base from a position that would not allow space for the departures; and could conflict with the Mooney. When I told the Skyhawk to turn out to the west and square his base (reminding him that I said I would tell him when to turn base); I believe I lost awareness of where the Mooney was on final; and instead told a Skylane of the position of the Mooney upwind as I cleared him for take off without remembering that the Mooney was so close in on final! I thought I had a hole for the departure; but I did not. I saw the inbound Mooney short final and immediately issued a go around that was acknowledged by the pilot as he began a climb. After the Skylane was established upwind; he acknowledged that he had the Mooney ahead in sight. After the incident; I took steps to regain control of the pattern by restricting pattern work and holding aircraft outside Class D until I was confident that I regained full awareness of my traffic situation. In hindsight; I needed to take steps earlier to gain greater control of the pattern as traffic was building. This event is a sobering learning experience about my own personal signs of overload developing; and I will apply these personal lessons learned in the future. The bottom line was my scan; my scan of strip bays and out the window broke down and I lost situational awareness of the position of the Mooney on final. I fell behind the volume of traffic that was inbound to the airport at that time; and allowed a pilot's miscue (unplanned early base turn) distract me into inadvertently issuing a badly timed take off clearance.

Data retrieved from NASA's ASRS site as of July 2013 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.