Aero Commander 500 Series
Air Traffic Control Developmental
Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Separated Traffic
Human Factors
Cleveland was on a north flow. An AC50 was 15 miles southwest of the Tower talking to RADAR. RADAR pointed the AC50 out to the Tower requesting to descend into BKL on a Visual Approach. I accepted the point out. When CTL was about 4 miles southwest of Cleveland; I had the AC50 in sight and I cleared a B737 for take off on runway headed. The B737 had a release time that I was trying to meet. It was my intention that the B737 would be airborne well in front of the AC50. The B737 did not begin takeoff roll as quickly as I anticipated. When the B737 rotated I realized that the aircraft was not ahead of the AC50. I turned the B737 northbound to 035 heading but the AC50 also turned northbound in the Visual Approach. I stopped the B737's altitude at 3;000 FT and turned the aircraft farther north to a 360 heading. Once the two aircraft were no longer in conflict; I shipped the B737 to departure. I had both aircraft in sight at all times and I was talking to the B737 until the necessary RADAR separation was achieved. The incident was a poor judgment call that resulted in unsafe proximity. In the future; I will not attempt to beat an airborne aircraft with one that is still on the ground and I will take into account that the pilot will start takeoff roll at their discretion.
CLE Controller described a potential conflict event when he/she departed an air carrier trying to get ahead of airborne traffic landing at an adjacent airport.