ZOB controller lost separation complicated by WX and radar problems.

Attributes
ACN	590745
Time
Date	200308
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dxo.vor
State Reference	MI
Altitude	msl bound lower : 18000 msl bound upper : 19000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : holding
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	cruise : holding
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
ASRS Report	590745
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	aircraft equipment : tcas other controllera
Consequence	faa : investigated
Miss Distance	horizontal : 18000 vertical : 800
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Traffic was heavy with holding for dtw due to WX along with deviations around WX. The radar and radar sites were subject to power outages, targets were jumping around on the dsr display. When I started a track for B737-300, I had believed it to be his correct position and then issued a descent clearance and turns, inbound for dtw, it was after the pilot advised me of an RA that I was unsure of position of aircraft at the time. Clearance was issued and reported the incident to my supervisor.

Original NASA ASRS Text

Title: ZOB CTLR LOST SEPARATION COMPLICATED BY WX AND RADAR PROBS.

Narrative: TFC WAS HVY WITH HOLDING FOR DTW DUE TO WX ALONG WITH DEVS AROUND WX. THE RADAR AND RADAR SITES WERE SUBJECT TO PWR OUTAGES, TARGETS WERE JUMPING AROUND ON THE DSR DISPLAY. WHEN I STARTED A TRACK FOR B737-300, I HAD BELIEVED IT TO BE HIS CORRECT POS AND THEN ISSUED A DSCNT CLRNC AND TURNS, INBOUND FOR DTW, IT WAS AFTER THE PLT ADVISED ME OF AN RA THAT I WAS UNSURE OF POS OF ACFT AT THE TIME. CLRNC WAS ISSUED AND RPTED THE INCIDENT TO MY SUPVR.

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.