C90 controller experienced operational error at 4000 ft with 2 mdw arrs while conducting controller ...

Attributes
ACN	617805
Time
Date	200405
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mdw.airport
State Reference	IL
Altitude	msl single value : 4000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach descent : intermediate altitude
Route In Use	approach : traffic pattern arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : c90.tracon
Operator	general aviation : corporate
Make Model Name	Beechjet 400
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude descent : approach
Route In Use	approach : traffic pattern arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach instruction : instructor
Qualification	controller : radar controller : non radar pilot : private pilot : instrument
Experience	controller non radar : 6.5 controller radar : 22.5 flight time total : 2186
ASRS Report	617805
Person 2
Affiliation	government : faa
Function	controller : approach instruction : trainee
Qualification	controller : developmental
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert other controllera
Resolutory Action	controller : issued alert controller : issued new clearance
Consequence	faa : investigated
Miss Distance	horizontal : 9000 vertical : 0
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was narrating to developmental after taking position. I was explaining the thought process and working the airplanes. Traffic was moderate to heavy although I had it 'set up,' I missed the turn from downwind to base. I attempted to turn both aircraft. The P180 turned, at what appeared to be a very slow rate.

Original NASA ASRS Text

Title: C90 CTLR EXPERIENCED OPERROR AT 4000 FT WITH 2 MDW ARRS WHILE CONDUCTING CTLR TRAINING.

Narrative: I WAS NARRATING TO DEVELOPMENTAL AFTER TAKING POS. I WAS EXPLAINING THE THOUGHT PROCESS AND WORKING THE AIRPLANES. TFC WAS MODERATE TO HVY ALTHOUGH I HAD IT 'SET UP,' I MISSED THE TURN FROM DOWNWIND TO BASE. I ATTEMPTED TO TURN BOTH ACFT. THE P180 TURNED, AT WHAT APPEARED TO BE A VERY SLOW RATE.

Data retrieved from NASA's ASRS site as of July 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.

C90 controller experienced operational error at 4000 ft with 2 mdw arrs while conducting controller training.