A300
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
Aircraft X was climbing to 8;000 FT; leaving 6;300 FT when CPC-IT issued a climb to 7;000 FT to Aircraft Y as well as turning them to a 350 heading. When Aircraft Y was at 5;800 FT; I instructed the CPC-IT to stop them at 6;000 FT as Aircraft X had leveled his climb rate. By the time the CPC-IT issued the 6;000 FT; Aircraft Y was above it and had to descend back down and separation was lost. Instead of instructing the CPC-IT to stop Aircraft Y; I should have just stopped them myself.
TRACON Controller providing OJT described a loss of separation when instructing the Developmental to make a transmission in lieu of amending the instruction directly to the aircraft.