Approach controller providing OJT described a loss of separation event when the developmental failed...

Narrative:

A BE58 was on vectors to L38 airport and in a slow descent down to 3;000 ft. A BE20 was on vectors; just flying around in our airspace burning fuel prior to landing and level at 5;000 ft. My developmental was a little distracted and started to take action when the airplanes were approximately 10 miles apart and on converging courses. He issued a turn to the BE20; 'turn left 30 degrees'; the BE58 was still slow descending when I told the BE20 to climb and maintain 6;000 ft and turn left heading 270. Traffic was called by the developmental; the BE58 eventually had the BE20 in sight and said 'king air in sight no factor'. The proximity of the 2 aircraft at this point was 2 miles and 700 ft with the BE58 out of 4;900 ft descending to 3;000 ft and the BE20 out of 5;600 ft in a climb to 6;000 ft. The aircraft flight paths never crossed. Mode 'C' variance may have been applicable in this situation; but I'm not too sure. [I should have] stepped in much sooner and not let the developmental get himself in a bind like that.

Original NASA ASRS Text

Title: Approach Controller providing OJT described a loss of separation event when the developmental failed to initiate enough corrective action to assure separation.

Narrative: A BE58 was on vectors to L38 airport and in a slow descent down to 3;000 FT. A BE20 was on vectors; just flying around in our airspace burning fuel prior to landing and level at 5;000 FT. My developmental was a little distracted and started to take action when the airplanes were approximately 10 miles apart and on converging courses. He issued a turn to the BE20; 'turn left 30 degrees'; the BE58 was still slow descending when I told the BE20 to climb and maintain 6;000 FT and turn left heading 270. Traffic was called by the developmental; the BE58 eventually had the BE20 in sight and said 'King Air in sight no factor'. The proximity of the 2 aircraft at this point was 2 miles and 700 FT with the BE58 out of 4;900 FT descending to 3;000 FT and the BE20 out of 5;600 FT in a climb to 6;000 FT. The aircraft flight paths never crossed. Mode 'C' variance may have been applicable in this situation; but I'm not too sure. [I should have] stepped in much sooner and not let the developmental get himself in a bind like that.

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.

Attributes
ACN	945630
Time
Date	201104
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Aircraft 1
Make Model Name	Baron 58/58TC
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Super King Air 200
Flight Phase	Climb
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Approach controller providing OJT described a loss of separation event when the developmental failed to initiate enough corrective action to assure separation.