Narrative:

While working a radar position; I had a perfect situation for the use of visual separation; because one of the aircraft was extremely small (C210) and the other an air carrier (737). Before I applied visual separation I discussed the situation and fact that I was about to use visual separation with the pilot of the C210. I verified with the pilot of the C210 that he was comfortable with the use of visual separation and comfortable with the wake turbulence of the 737 even though the 737 is not a heavy. After the conversation I then restated that visual separation would be in use to the C210 pilot and for him to maintain visual separation. I was then told because of the way I delivered the clearance that I did not get an acknowledgment from the C210 pilot. I had had an error. First; I felt there was no doubt there was an acknowledgment because we had already had a conversation about the use of visual separation. After the conversation; I restated to the pilot of the C210 to maintain visual separation. Secondly; I have done it this way ever since we have been able to use visual separation in the en route environment. Thirdly; if there is a change in what they expect in a clearance; why did I not get some kind of briefing on it? All of this was done to provide better service to both aircraft and avoid having to vector them out of each other's way when they would never be inside 4 miles of each other. This procedure should be one of the simplest procedures we use; yet it has become one of the most difficult procedures and more and more people are refusing to use it which means we are providing less and less service. Number one; we need to simplify the procedure. You have so many boxes to check to use visual separation; it is almost impossible to use it. Secondly; when we constantly change rules; it is very difficult to become proficient with that tool. The rules for visual separation have obviously changed again; and I did not get trained or briefed yet the system wants to blame me for its idiosyncrasies. Safety was never compromised. Both pilots were very comfortable; and I'm sure quite pleased with the service; yet after 29 years of ATC I'm explaining why this happened. Obviously there is something wrong with the system.

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Original NASA ASRS Text

Title: ARTCC Controller reported he was advised of an operational error due to the use of improper phraseology during visual separation.

Narrative: While working a radar position; I had a perfect situation for the use of visual separation; because one of the aircraft was extremely small (C210) and the other an air carrier (737). Before I applied visual separation I discussed the situation and fact that I was about to use visual separation with the pilot of the C210. I verified with the pilot of the C210 that he was comfortable with the use of visual separation and comfortable with the wake turbulence of the 737 even though the 737 is not a heavy. After the conversation I then restated that visual separation would be in use to the C210 pilot and for him to maintain visual separation. I was then told because of the way I delivered the clearance that I did not get an acknowledgment from the C210 pilot. I had had an error. First; I felt there was no doubt there was an acknowledgment because we had already had a conversation about the use of visual separation. After the conversation; I restated to the pilot of the C210 to maintain visual separation. Secondly; I have done it this way ever since we have been able to use visual separation in the en route environment. Thirdly; if there is a change in what they expect in a clearance; why did I not get some kind of briefing on it? All of this was done to provide better service to both aircraft and avoid having to vector them out of each other's way when they would never be inside 4 miles of each other. This procedure should be one of the simplest procedures we use; yet it has become one of the most difficult procedures and more and more people are refusing to use it which means we are providing less and less service. Number one; we need to simplify the procedure. You have so many boxes to check to use visual separation; it is almost impossible to use it. Secondly; when we constantly change rules; it is very difficult to become proficient with that tool. The rules for visual separation have obviously changed again; and I did not get trained or briefed yet the system wants to blame me for its idiosyncrasies. Safety was never compromised. Both pilots were very comfortable; and I'm sure quite pleased with the service; yet after 29 years of ATC I'm explaining why this happened. Obviously there is something wrong with the system.

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.