Cmh approach controller described radar reception event when aircraft target utilizing mode-south eq...

Attributes
ACN	813614
Time
Date	200811
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cmh.airport
State Reference	OH
Altitude	msl single value : 4200
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : cmh.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 26
ASRS Report	813614
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Navigational Facility
Primary Problem	Navigational Facility

Narrative:

It was a late afternoon with very good VFR conditions. I was working north radar; utilizing our cmh mode south radar. Approximately 30 mi north; moving sbound; I noticed a primary-only (radar) target; in which there is neither a transponder code nor an altitude showing. The target remained as a radar target for at least 10 mi. However; a xchk; utilizing a separate radar display with the long-range ARTCC radar located at london; oh; (qwo -- approximately 30 NM west of cmh) selected; showed a solid transponder reply from this aircraft the entire period; indicating that the aircraft was squawking 1200 and at 4200 ft MSL. On a good VFR day like today; it is easy to see this phenomenon; in which if one looked at such aircraft 'only' with our cmh mode south; it would appear that many low-end GA aircraft have intermittent xponders.

Original NASA ASRS Text

Title: CMH APPROACH CONTROLLER DESCRIBED RADAR RECEPTION EVENT WHEN AIRCRAFT TARGET UTILIZING MODE-S EQUIPMENT FAILED TO DISPLAY TRANSPONDER AND ALTITUDE INFORMATION; ALLEGING CENTER RADAR DISPLAYED BOTH SETS OF INFORMATION.

Narrative: IT WAS A LATE AFTERNOON WITH VERY GOOD VFR CONDITIONS. I WAS WORKING N RADAR; UTILIZING OUR CMH MODE S RADAR. APPROX 30 MI N; MOVING SBOUND; I NOTICED A PRIMARY-ONLY (RADAR) TARGET; IN WHICH THERE IS NEITHER A XPONDER CODE NOR AN ALT SHOWING. THE TARGET REMAINED AS A RADAR TARGET FOR AT LEAST 10 MI. HOWEVER; A XCHK; UTILIZING A SEPARATE RADAR DISPLAY WITH THE LONG-RANGE ARTCC RADAR LOCATED AT LONDON; OH; (QWO -- APPROX 30 NM W OF CMH) SELECTED; SHOWED A SOLID XPONDER REPLY FROM THIS ACFT THE ENTIRE PERIOD; INDICATING THAT THE ACFT WAS SQUAWKING 1200 AND AT 4200 FT MSL. ON A GOOD VFR DAY LIKE TODAY; IT IS EASY TO SEE THIS PHENOMENON; IN WHICH IF ONE LOOKED AT SUCH ACFT 'ONLY' WITH OUR CMH MODE S; IT WOULD APPEAR THAT MANY LOW-END GA ACFT HAVE INTERMITTENT XPONDERS.

Data retrieved from NASA's ASRS site as of May 2009 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.

Cmh approach controller described radar reception event when aircraft target utilizing mode-south equipment failed to display transponder and altitude information; alleging center radar displayed both sets of information.