Controller reports that a radar site has numerous false targets.

Attributes
ACN	237193
Time
Date	199303
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zab
State Reference	NM
Altitude	msl bound lower : 37000 msl bound upper : 37000
Aircraft 1
Controlling Facilities	artcc : zab
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 16
ASRS Report	237193
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other
Situations
Navigational Aid	Unspecified

Narrative:

The ama radar site is causing numerous false targets to appear north of ama. This is causing an unsafe condition because it may not be possible to determine if a target is false, or if it is a real mode C intruder. Several times a false target has been acquired by the mode C intruder patch, and has caused a TA with a known aircraft. On mar/xa/93, I issued a descent clearance to an air carrier X flight because of a TA on a mode C intruder. Just after issuing the descent, the mode C intruder target disappeared, it was a false target. There has been at least one other incident similar to mine. On mar/xb/93, there were 30 false targets reported, and on mar/xc/93, there were 16 reported. There may have been more that the controllers did not have time to record. These false targets are a safety hazard, and have been occurring for a long time. They have worked on the system, but it does not seem to be much of a priority. My concern is that one time, there will be a 'real' mode C intruder, but because we have so many false targets, the controller will choose to ignore it, and safety will be compromised.

Original NASA ASRS Text

Title: CTLR RPTS THAT A RADAR SITE HAS NUMEROUS FALSE TARGETS.

Narrative: THE AMA RADAR SITE IS CAUSING NUMEROUS FALSE TARGETS TO APPEAR N OF AMA. THIS IS CAUSING AN UNSAFE CONDITION BECAUSE IT MAY NOT BE POSSIBLE TO DETERMINE IF A TARGET IS FALSE, OR IF IT IS A REAL MODE C INTRUDER. SEVERAL TIMES A FALSE TARGET HAS BEEN ACQUIRED BY THE MODE C INTRUDER PATCH, AND HAS CAUSED A TA WITH A KNOWN ACFT. ON MAR/XA/93, I ISSUED A DSCNT CLRNC TO AN ACR X FLT BECAUSE OF A TA ON A MODE C INTRUDER. JUST AFTER ISSUING THE DSCNT, THE MODE C INTRUDER TARGET DISAPPEARED, IT WAS A FALSE TARGET. THERE HAS BEEN AT LEAST ONE OTHER INCIDENT SIMILAR TO MINE. ON MAR/XB/93, THERE WERE 30 FALSE TARGETS RPTED, AND ON MAR/XC/93, THERE WERE 16 RPTED. THERE MAY HAVE BEEN MORE THAT THE CTLRS DID NOT HAVE TIME TO RECORD. THESE FALSE TARGETS ARE A SAFETY HAZARD, AND HAVE BEEN OCCURRING FOR A LONG TIME. THEY HAVE WORKED ON THE SYS, BUT IT DOES NOT SEEM TO BE MUCH OF A PRIORITY. MY CONCERN IS THAT ONE TIME, THERE WILL BE A 'REAL' MODE C INTRUDER, BUT BECAUSE WE HAVE SO MANY FALSE TARGETS, THE CTLR WILL CHOOSE TO IGNORE IT, AND SAFETY WILL BE COMPROMISED.

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.