Narrative:

I cleared the aircraft for takeoff from runway xx. As I delivered aircraft X's flight strip to the radar position; I observed the position of air carrier Y taxiing to runway yy. Air carrier Y called for clearance a few seconds later. I checked the position of aircraft X and the aircraft was still stationary; so I cleared air carrier Y for takeoff on runway yy. I was anticipating that air carrier Y would clear the intersecting flight path of aircraft X before aircraft X could start its departure roll; based on aircraft X's position on taxiway a and that aircraft X had not yet started taxiing to runway xx. I became engaged in other duties; posting strips and assisting the approach controller. I did not see the aircraft departing. Air carrier Y asked if another aircraft was a go-around. Suspecting that an aircraft had made an approach that was not talking to me; I searched the approach ends of the runways and the surrounding airspace for another aircraft. There were none. I looked at the positions of the 2 aircraft under my control. Air carrier Y was well past the departure end of runway yy by approximately a mile to a mile and a half; and aircraft X was just over the tree line approximately 1/4 mile off the departure end of runway xx and were not in conflict. Air carrier Y asked again if there was another aircraft; a cessna or a piper; on a go-around. There were no piper aircraft in the area and I didn't consider it plausible that air carrier Y was referring to aircraft X. During this time; the approach controller was having difficulty with an aircraft flight plan that had timed out and was at the fdio machine trying to enter a flight plan. I was watching the radar scope and trying to assist with the flight plan also. Other controllers were in the cab to make position rotations. I was confused and disoriented trying to find another aircraft; while helping the approach controller; and accomplishing my other duties. I told air carrier Y; 'yes sir.' I don't know why; I didn't know what else to say to him. I was still under the assumption that there had been another aircraft in the airspace that went around; yet I couldn't find it. At the time of the occurrence; I was working as the shift controller in charge; cab controller in charge; local control; ground control; flight data; and clearance delivery positions. Neither aircraft involved in the incident made any statement which would lead me to believe there was a loss of separation. Of the several controllers in the tower when the incident happened; none of them alerted me to a potential unsafe situation. None acted to avert the unsafe situation; and none made any statement to me that there had been a loss of separation. As I didn't see the loss of separation and without notice from the pilots or the witnessing controllers; I did not know there had been an actual loss of separation. I've come to find out that air carrier Y and aircraft X were an operational error. I did not see the incident. I would not have believed there was a loss of separation until I saw the video playback.

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Original NASA ASRS Text

Title: A C172 Instructor Pilot reported an NMAC with an EMB 145 shortly after takeoff. Reports from Tower personnel indicate the Tower Controller may have simply forgotten about issuing a clearance to the C172; which was delayed a bit in reacting to the takeoff clearance.

Narrative: I cleared the aircraft for takeoff from Runway XX. As I delivered Aircraft X's flight strip to the RADAR position; I observed the position of Air Carrier Y taxiing to Runway YY. Air Carrier Y called for clearance a few seconds later. I checked the position of Aircraft X and the aircraft was still stationary; so I cleared Air Carrier Y for takeoff on Runway YY. I was anticipating that Air Carrier Y would clear the intersecting flight path of Aircraft X before Aircraft X could start its departure roll; based on Aircraft X's position on Taxiway A and that Aircraft X had not yet started taxiing to Runway XX. I became engaged in other duties; posting strips and assisting the Approach Controller. I did not see the aircraft departing. Air Carrier Y asked if another aircraft was a go-around. Suspecting that an aircraft had made an approach that was not talking to me; I searched the approach ends of the runways and the surrounding airspace for another aircraft. There were none. I looked at the positions of the 2 aircraft under my control. Air Carrier Y was well past the departure end of Runway YY by approximately a mile to a mile and a half; and Aircraft X was just over the tree line approximately 1/4 mile off the departure end of Runway XX and were not in conflict. Air Carrier Y asked again if there was another aircraft; a Cessna or a Piper; on a go-around. There were no Piper aircraft in the area and I didn't consider it plausible that Air Carrier Y was referring to Aircraft X. During this time; the Approach Controller was having difficulty with an aircraft flight plan that had timed out and was at the FDIO machine trying to enter a flight plan. I was watching the RADAR scope and trying to assist with the flight plan also. Other controllers were in the cab to make position rotations. I was confused and disoriented trying to find another aircraft; while helping the Approach Controller; and accomplishing my other duties. I told Air Carrier Y; 'Yes sir.' I don't know why; I didn't know what else to say to him. I was still under the assumption that there had been another aircraft in the airspace that went around; yet I couldn't find it. At the time of the occurrence; I was working as the shift CIC; Cab CIC; Local Control; Ground Control; Flight Data; and Clearance Delivery positions. Neither aircraft involved in the incident made any statement which would lead me to believe there was a loss of separation. Of the several controllers in the Tower when the incident happened; none of them alerted me to a potential unsafe situation. None acted to avert the unsafe situation; and none made any statement to me that there had been a loss of separation. As I didn't see the loss of separation and without notice from the pilots or the witnessing controllers; I did not know there had been an actual loss of separation. I've come to find out that Air Carrier Y and Aircraft X were an operational error. I did not see the incident. I would not have believed there was a loss of separation until I saw the video playback.

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.