ARTCC radar ZME controller observes unknown traffic pop up at 5000 ft within 1 mi of an IFR BE36 lev...

Attributes
ACN	541298
Time
Date	200203
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : tha.airport
State Reference	TN
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme.artcc tower : sln.tower
Operator	general aviation : personal
Make Model Name	Bonanza 36
Operating Under FAR Part	Part 91
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 14 controller time certified in position1 : 14
ASRS Report	541298
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	atc equipment : conflict alert atc equipment other atc equipment : radar other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued advisory flight crew : took evasive action none taken : detected after the fact
Miss Distance	horizontal : 6000 vertical : 0
Supplementary
Problem Areas	Airspace Structure ATC Facility
Primary Problem	Airspace Structure

Narrative:

The conflict alert (en route) is based at 5000 ft. The VFR aircraft was only observed, when the conflict alert activated at 5100 ft. Callback conversation with reporter revealed the following information: the reporter said radar coverage was hit and miss above 4000 ft. He said the traffic did not appear to have a transponder turned on and was first observed 1 mi ahead of the BE36. Since the incident, the reporter said the radar parameters have been lowered to 2500 ft. When asked if this type of incident has happened before, the reporter said another controller had a similar problem less than 1 yr ago.

Original NASA ASRS Text

Title: ARTCC RADAR ZME CTLR OBSERVES UNKNOWN TFC POP UP AT 5000 FT WITHIN 1 MI OF AN IFR BE36 LEVELING AT 5000 FT.

Narrative: THE CONFLICT ALERT (ENRTE) IS BASED AT 5000 FT. THE VFR ACFT WAS ONLY OBSERVED, WHEN THE CONFLICT ALERT ACTIVATED AT 5100 FT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID RADAR COVERAGE WAS HIT AND MISS ABOVE 4000 FT. HE SAID THE TFC DID NOT APPEAR TO HAVE A XPONDER TURNED ON AND WAS FIRST OBSERVED 1 MI AHEAD OF THE BE36. SINCE THE INCIDENT, THE RPTR SAID THE RADAR PARAMETERS HAVE BEEN LOWERED TO 2500 FT. WHEN ASKED IF THIS TYPE OF INCIDENT HAS HAPPENED BEFORE, THE RPTR SAID ANOTHER CTLR HAD A SIMILAR PROB LESS THAN 1 YR AGO.

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.

ARTCC radar ZME controller observes unknown traffic pop up at 5000 ft within 1 mi of an IFR BE36 leveling at 5000 ft.