Narrative:

We have had a continuous problem with 'false targets' being displayed by the ASR-9 radar at rdu. This has been ongoing since september of 1996. If you examine the facility operations logs, you will see 'numerous false targets' has been a continuously carried over item. Data was collected, and some modifications made to the system, but none of these actions resolved the problem. Any time I ask about the status of the problem, I am told it is a national problem and they can do nothing locally. On some days you will see as many as 15-20, all within 20 miles of the airport. Callback conversation with reporter revealed the following information: supplemental information: a tower specialist confirmed this problem. False, primary targets will appear and stay on the radar display for several mins at a time. The specialist advised that the false targets seem to group northeast and southwest of the airport, five to twenty miles out from the airport, most frequently grouped in the vicinity of the approach and departure areas for runways 23 left/right. The condition exists year around. The specialist advised that 'false targets' appear weekly on the facility daily operations log. The specialists advised of a recent incident when false targets were present for an 'extended period of time' a long the runway 23R approach path. An air carrier initiated an evasive TCAS RA climb because an unidentified aircraft transiting the final approach course abeam the OM was not issued by the local controller.

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Original NASA ASRS Text

Title: RDU CTLR ALLEGES CONTINUOUS ASR-9 FALSE TARGET PROBS SINCE 1996.

Narrative: WE HAVE HAD A CONTINUOUS PROB WITH 'FALSE TARGETS' BEING DISPLAYED BY THE ASR-9 RADAR AT RDU. THIS HAS BEEN ONGOING SINCE SEPTEMBER OF 1996. IF YOU EXAMINE THE FACILITY OPS LOGS, YOU WILL SEE 'NUMEROUS FALSE TARGETS' HAS BEEN A CONTINUOUSLY CARRIED OVER ITEM. DATA WAS COLLECTED, AND SOME MODIFICATIONS MADE TO THE SYS, BUT NONE OF THESE ACTIONS RESOLVED THE PROB. ANY TIME I ASK ABOUT THE STATUS OF THE PROB, I AM TOLD IT IS A NATIONAL PROB AND THEY CAN DO NOTHING LOCALLY. ON SOME DAYS YOU WILL SEE AS MANY AS 15-20, ALL WITHIN 20 MILES OF THE ARPT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: SUPPLEMENTAL INFO: A TWR SPECIALIST CONFIRMED THIS PROB. FALSE, PRIMARY TARGETS WILL APPEAR AND STAY ON THE RADAR DISPLAY FOR SEVERAL MINS AT A TIME. THE SPECIALIST ADVISED THAT THE FALSE TARGETS SEEM TO GROUP NE AND SW OF THE ARPT, FIVE TO TWENTY MILES OUT FROM THE ARPT, MOST FREQUENTLY GROUPED IN THE VICINITY OF THE APCH AND DEP AREAS FOR RWYS 23 L/R. THE CONDITION EXISTS YEAR AROUND. THE SPECIALIST ADVISED THAT 'FALSE TARGETS' APPEAR WEEKLY ON THE FAC DAILY OPS LOG. THE SPECIALISTS ADVISED OF A RECENT INCIDENT WHEN FALSE TARGETS WERE PRESENT FOR AN 'EXTENDED PERIOD OF TIME' A LONG THE RWY 23R APCH PATH. AN ACR INITIATED AN EVASIVE TCAS RA CLB BECAUSE AN UNIDENTIFIED ACFT TRANSITING THE FINAL APCH COURSE ABEAM THE OM WAS NOT ISSUED BY THE LCL CTLR.

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.