ZTL radar at the maiden site is generating false targets off of the real targets, which would be dis...

Narrative:

Aircraft #1 (X), PA32, was en route from avl to rdu. He was 1 of 2 aircraft I was working at the time. I scanned the scope and saw a mode C intruder 4 mi in front of and head on with the PA32. I issued the traffic as an unknown. The target was aircraft #2 (Y), inbound to clt. The real aircraft/target was 50 mi away. Aircraft #2 (Y) was landing clt. Had the aircraft been descending when the incident occurred I would have had no other choice but to give aircraft #1 (X) an immediate, evasive maneuver. The maiden radar site (qrm) has a long history of problems and outages. In the last 3 weeks, there have been over a dozen radar trouble report forms filled out on this site. Callback conversation with reporter revealed the following information: reporter said this problem began in earnest about 3 months ago. Since then, there have been approximately 40 trouble tickets turned in to radar maintenance detailing the false target problem. The dates range from mid-jan to mid- march. ZTL's maiden radar is an old ARSR model #1. This situation does not happen everyday. It appears to happen only when the WX is other than clear. Reporter also stated the ring around gives you split beacons that would appear at the same mileage anywhere along the 360 degree radius. This condition manifested itself on other radar sectors utilizing the same radar site. Reporter stated his recent experience with this anomaly was when a limited data block suddenly appeared on his radar, that was head on into his traffic. The question whether to give his traffic a drastic turn or not, was utmost in his mind. Since the facility installed a new beacon interrogator awhile back, the system is more sensitive than the one they replaced, this may account for some of the problems. A huge subdivision has been built in close proximity to the radar site. Reporter believes this is the reason they are having problems. The buildings are acting as reflectors.

Original NASA ASRS Text

Title: ZTL RADAR AT THE MAIDEN SITE IS GENERATING FALSE TARGETS OFF OF THE REAL TARGETS, WHICH WOULD BE DISPLAYED IN OTHER RADAR SECTORS. ARTCC CTLR THEN BELIEVES THEY HAVE UNKNOWN TFC THAT CAME OUT OF NOWHERE. RPTR HAS INDICATED THAT THIS HAS BEEN AN ON-GOING PROB.

Narrative: ACFT #1 (X), PA32, WAS ENRTE FROM AVL TO RDU. HE WAS 1 OF 2 ACFT I WAS WORKING AT THE TIME. I SCANNED THE SCOPE AND SAW A MODE C INTRUDER 4 MI IN FRONT OF AND HEAD ON WITH THE PA32. I ISSUED THE TFC AS AN UNKNOWN. THE TARGET WAS ACFT #2 (Y), INBOUND TO CLT. THE REAL ACFT/TARGET WAS 50 MI AWAY. ACFT #2 (Y) WAS LNDG CLT. HAD THE ACFT BEEN DSNDING WHEN THE INCIDENT OCCURRED I WOULD HAVE HAD NO OTHER CHOICE BUT TO GIVE ACFT #1 (X) AN IMMEDIATE, EVASIVE MANEUVER. THE MAIDEN RADAR SITE (QRM) HAS A LONG HISTORY OF PROBS AND OUTAGES. IN THE LAST 3 WKS, THERE HAVE BEEN OVER A DOZEN RADAR TROUBLE RPT FORMS FILLED OUT ON THIS SITE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID THIS PROB BEGAN IN EARNEST ABOUT 3 MONTHS AGO. SINCE THEN, THERE HAVE BEEN APPROX 40 TROUBLE TICKETS TURNED IN TO RADAR MAINT DETAILING THE FALSE TARGET PROB. THE DATES RANGE FROM MID-JAN TO MID- MARCH. ZTL'S MAIDEN RADAR IS AN OLD ARSR MODEL #1. THIS SIT DOES NOT HAPPEN EVERYDAY. IT APPEARS TO HAPPEN ONLY WHEN THE WX IS OTHER THAN CLR. RPTR ALSO STATED THE RING AROUND GIVES YOU SPLIT BEACONS THAT WOULD APPEAR AT THE SAME MILEAGE ANYWHERE ALONG THE 360 DEG RADIUS. THIS CONDITION MANIFESTED ITSELF ON OTHER RADAR SECTORS UTILIZING THE SAME RADAR SITE. RPTR STATED HIS RECENT EXPERIENCE WITH THIS ANOMALY WAS WHEN A LIMITED DATA BLOCK SUDDENLY APPEARED ON HIS RADAR, THAT WAS HEAD ON INTO HIS TFC. THE QUESTION WHETHER TO GIVE HIS TFC A DRASTIC TURN OR NOT, WAS UTMOST IN HIS MIND. SINCE THE FACILITY INSTALLED A NEW BEACON INTERROGATOR AWHILE BACK, THE SYS IS MORE SENSITIVE THAN THE ONE THEY REPLACED, THIS MAY ACCOUNT FOR SOME OF THE PROBS. A HUGE SUBDIVISION HAS BEEN BUILT IN CLOSE PROX TO THE RADAR SITE. RPTR BELIEVES THIS IS THE REASON THEY ARE HAVING PROBS. THE BUILDINGS ARE ACTING AS REFLECTORS.

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.

Attributes
ACN	428708
Time
Date	199902
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gso
State Reference	NC
Altitude	msl bound lower : 7000 msl bound upper : 7000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	PA-32 Cherokee Six/Lance/Saratoga
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Jetstream 32
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Experience	flight time total : 17
ASRS Report	428708
Person 2
Affiliation	Other
Function	flight crew : single pilot
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Air Traffic Incident	other
Situations
ATC Facility	other physical facility

ZTL radar at the maiden site is generating false targets off of the real targets, which would be displayed in other radar sectors. ARTCC controller then believes they have unknown traffic that came out of nowhere. Reporter has indicated that this has been an on-going problem.