Narrative:

I was providing radar OJT. Aircraft #1 was inbound to day via rid; the trainee had previously descended it to 170 FPM from FL240. Aircraft #2 was departing cvg northbound toward mie. The trainee climbed it to 16000 ft and issued direct routing to pmm. In order to comply with day ATCT LOA; I advised the trainee to rapidly descend aircraft #1 to 11000 ft and turn it 15 degrees left. The turn couldn't be issued right away because of ord traffic which was being vectored for spacing; but it was given once that traffic was cleared. I also advised the trainee to climb aircraft #2 to FL220 (requested altitude). I then advised a 20 degree left turn for aircraft #2. When conflict alert activated; I advised an additional 20 degree left turn which was given. Aedep activated at 4.5 mi and 200 ft (at about 16500 ft). In this case; I chose to let the trainee issue the control instructions instead of taking over and doing it myself. I feel that the extra time it took to relay to the trainee was the difference between the aircraft being separated and separation being lost. In the future; I will issue those instructions myself.

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Original NASA ASRS Text

Title: ZID CTLR EXPERIENCED OPERROR AT 17000 FT WITH CLBING AND DSNDING ACFT WHILE PROVIDING OJT.

Narrative: I WAS PROVIDING RADAR OJT. ACFT #1 WAS INBOUND TO DAY VIA RID; THE TRAINEE HAD PREVIOUSLY DSNDED IT TO 170 FPM FROM FL240. ACFT #2 WAS DEPARTING CVG NBOUND TOWARD MIE. THE TRAINEE CLBED IT TO 16000 FT AND ISSUED DIRECT ROUTING TO PMM. IN ORDER TO COMPLY WITH DAY ATCT LOA; I ADVISED THE TRAINEE TO RAPIDLY DSND ACFT #1 TO 11000 FT AND TURN IT 15 DEGS L. THE TURN COULDN'T BE ISSUED RIGHT AWAY BECAUSE OF ORD TFC WHICH WAS BEING VECTORED FOR SPACING; BUT IT WAS GIVEN ONCE THAT TFC WAS CLRED. I ALSO ADVISED THE TRAINEE TO CLB ACFT #2 TO FL220 (REQUESTED ALT). I THEN ADVISED A 20 DEG L TURN FOR ACFT #2. WHEN CONFLICT ALERT ACTIVATED; I ADVISED AN ADDITIONAL 20 DEG L TURN WHICH WAS GIVEN. AEDEP ACTIVATED AT 4.5 MI AND 200 FT (AT ABOUT 16500 FT). IN THIS CASE; I CHOSE TO LET THE TRAINEE ISSUE THE CTL INSTRUCTIONS INSTEAD OF TAKING OVER AND DOING IT MYSELF. I FEEL THAT THE EXTRA TIME IT TOOK TO RELAY TO THE TRAINEE WAS THE DIFFERENCE BTWN THE ACFT BEING SEPARATED AND SEPARATION BEING LOST. IN THE FUTURE; I WILL ISSUE THOSE INSTRUCTIONS MYSELF.

Data retrieved from NASA's ASRS site as of January 2009 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.