Citation X (C750)
Air Traffic Control Fully Certified
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Human Factors
A C750 was on a southeast vector to final for the airport at 040 MSL. A BE20 was northeast bound on an IFR en route flight plan via V363 at 050 MSL. I issued traffic for both aircraft; but when I went to descend the C750; I used the BE20's callsign. I noticed the BE20 descending out of 048 and I issued a climb back up to 050. However; the aircraft was in a descent; so he shows about 045 before his climb resumed. The C750 reported the BE20 in sight; but separation was already lost. Slow down my thought process and think of what I am saying before I say it. Listen to what I am saying and hear myself say it instead of being on phraseology auto pilot so to speak. If it sounds wrong it probably is.
TRACON Controller acknowledged a loss of separation event when 'thinking' one descent clearance but in fact 'issuing' another.