Narrative:

I was administering OJT to a radar trnee and the trnee descended an aircraft at 17000' (large transport X) through another aircraft at 16000' (large transport Y) when I took the frequency and vectored large transport Y, but we had 3 mi horizontal and 300' vertical sep.

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Original NASA ASRS Text

Title: CTLR TRAINEE DESCENDED ACR-LGT THROUGH THE ALT OF ANOTHER ACR-LGT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: I WAS ADMINISTERING OJT TO A RADAR TRNEE AND THE TRNEE DSNDED AN ACFT AT 17000' (LGT X) THROUGH ANOTHER ACFT AT 16000' (LGT Y) WHEN I TOOK THE FREQ AND VECTORED LGT Y, BUT WE HAD 3 MI HORIZ AND 300' VERT SEP.

Data retrieved from NASA's ASRS site as of August 2007 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.