Less than standard separation between air carrier and small transport.

Attributes
ACN	165477
Time
Date	199012
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : okk
State Reference	IN
Altitude	msl bound lower : 23000 msl bound upper : 23200
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zau tracon : ont
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller military : 4 controller non radar : 10 controller radar : 8 controller supervisory : 1
ASRS Report	165477
Person 2
Affiliation	government : faa
Function	controller : flight data
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	other other : unspecified atc
Consequence	faa : investigated
Miss Distance	horizontal : 1500 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Intra Facility Coordination Failure Operational Error

Narrative:

Air carrier X en route to ord via oxi V340. Air carrier X was descended out of FL240 to 16000'. The traffic was small transport Y en route to dtw via bvt-fwa-dtw. Traffic was not pointed out on my scope, so I was unaware of the traffic and did not see the limited data block on my scope prior to starting air carrier X down.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR AND SMT.

Narrative: ACR X ENRTE TO ORD VIA OXI V340. ACR X WAS DSNDED OUT OF FL240 TO 16000'. THE TFC WAS SMT Y ENRTE TO DTW VIA BVT-FWA-DTW. TFC WAS NOT POINTED OUT ON MY SCOPE, SO I WAS UNAWARE OF THE TFC AND DID NOT SEE THE LIMITED DATA BLOCK ON MY SCOPE PRIOR TO STARTING ACR X DOWN.

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.