Narrative:

I cleared a CRJ2 for take off on runway 18R. I then put an A319/320 into position behind them and told them about traffic on a 6 or 7 mile final. I wanted to get one more departure out behind this aircraft landed. I scanned the runway and the crj looked beyond 6;000 ft and airborne; I looked at the airbus which was still turning onto the runway and not fully facing down the runway. I cleared the airbus for take off feeling like the spacing was fine. The airbus departed a little faster than most other ones I have seen at this airport. I had already switched the crj to departure and waited a second to switch the airbus. When I switched them I believed I had enough spacing and that the front aircraft would speed up very soon. I cleared the other aircraft for take off with plenty of space that was never an issue and the aircraft on final landed safely. I continued working and someone called me on the land line and said 'scroll out and look at those first two'. I did and they were very close. The departure controller just started training and I am not sure all actions they took. I believe they just used altitude to keep them separated until they could diverge. I thought off the runway end to attempt visual separation between the two but decided against it because of low ceilings. Recommendation; I could have tried visual separation; I could have put one of the aircraft on a heading to keep them apart and coordinated something. I never even called the departure to let them know anything. This was an honest mistake and I have never had this type of problem before.

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Original NASA ASRS Text

Title: CLT Controller described a loss of separation event involving two successive departures from Runway 18.

Narrative: I cleared a CRJ2 for take off on Runway 18R. I then put an A319/320 into position behind them and told them about traffic on a 6 or 7 mile final. I wanted to get one more departure out behind this aircraft landed. I scanned the runway and the CRJ looked beyond 6;000 FT and airborne; I looked at the Airbus which was still turning onto the runway and not fully facing down the runway. I cleared the Airbus for take off feeling like the spacing was fine. The Airbus departed a little faster than most other ones I have seen at this airport. I had already switched the CRJ to Departure and waited a second to switch the Airbus. When I switched them I believed I had enough spacing and that the front aircraft would speed up very soon. I cleared the other aircraft for take off with plenty of space that was never an issue and the aircraft on final landed safely. I continued working and someone called me on the land line and said 'scroll out and look at those first two'. I did and they were very close. The Departure Controller just started training and I am not sure all actions they took. I believe they just used altitude to keep them separated until they could diverge. I thought off the runway end to attempt visual separation between the two but decided against it because of low ceilings. Recommendation; I could have tried visual separation; I could have put one of the aircraft on a heading to keep them apart and coordinated something. I never even called the Departure to let them know anything. This was an honest mistake and I have never had this type of problem before.

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.