Narrative:

The M20 was in route at 9;000 ft; west to east. The CRJ200 was a departure off cae runway 11. Traffic was slow and I only had 4 planes I think. I established radar contact with the CRJ200 on departure and put him on course to atl. The CRJ200 was out of about 4;000 ft when I switched him to ZJX. At the time the conflict with the 9;000 ft overflight M20 was about 15 to 20 miles away and I did not see it. I saw the conflict when the aircraft were about 6 to 7 miles apart and opposite direction to each other. I called to the aircraft I was talking to (the M20) and told him to turn right heading 180 immediately; and then gave him the traffic call. I did not wait for the response and keyed the ZJX center line and said turn the CRJ200 north my guy is going south. Both aircraft were on east/west lines opposite direction to each other. The CRJ200 heading 270; the M20 heading 090. I again called the M20 to turn right heading 180 immediately with no response. I made the call again; no response. Then the M20 called and said are you calling me? And I realized I had been using the wrong call sign. The call sign had a 'west' and I had been calling 'M'. The aircraft passed thanks to TCAS and a RA alert. I immediately asked the supervisor for relief. This near midair was completely my fault. I was complacent and focused on the departure. I gave him the same thing we always give them. The slowness of the position and routine of the departure lolled me into a false sense of awareness. I will never again take the routine operation of the departure; or for that matter any operation be it only one plane for granted again. I have 30 years ATC experience and this goes to show you can never let your guard down. I deeply regret my failure and realize that if TCAS had not been on the aircraft the outcome could have been catastrophically horrible. I have learned from this error and will be forever diligent.

Related reports:

Google
 

Original NASA ASRS Text

Title: CAE Departure Controller describes an airborne conflict that he allowed to develop between a CRJ200 climbing and a M20 at 9;000 FT. An incorrect call sign was used to turn the M20 and ultimately a TCAS RA aboard the CRJ separated the two aircraft.

Narrative: The M20 was in route at 9;000 FT; west to east. The CRJ200 was a departure off CAE Runway 11. Traffic was slow and I only had 4 planes I think. I established radar contact with the CRJ200 on departure and put him on course to ATL. The CRJ200 was out of about 4;000 FT when I switched him to ZJX. At the time the conflict with the 9;000 FT overflight M20 was about 15 to 20 miles away and I did not see it. I saw the conflict when the aircraft were about 6 to 7 miles apart and opposite direction to each other. I called to the aircraft I was talking to (the M20) and told him to turn right heading 180 immediately; and then gave him the traffic call. I did not wait for the response and keyed the ZJX Center line and said turn the CRJ200 north my guy is going south. Both aircraft were on east/west lines opposite direction to each other. The CRJ200 heading 270; the M20 heading 090. I again called the M20 to turn right heading 180 immediately with no response. I made the call again; no response. Then the M20 called and said are you calling me? And I realized I had been using the wrong call sign. The call sign had a 'W' and I had been calling 'M'. The aircraft passed thanks to TCAS and a RA alert. I immediately asked the Supervisor for relief. This near midair was completely my fault. I was complacent and focused on the departure. I gave him the same thing we always give them. The slowness of the position and routine of the departure lolled me into a false sense of awareness. I will never again take the routine operation of the departure; or for that matter any operation be it only one plane for granted again. I have 30 years ATC experience and this goes to show you can never let your guard down. I deeply regret my failure and realize that if TCAS had not been on the aircraft the outcome could have been catastrophically horrible. I have learned from this error and will be forever diligent.

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.