Narrative:

I was working moorpark radar and received a handoff from woodland sector on air carrier X near smo heading to join V23. I handed X off to ZLA sector 4 (via automation) and they accepted the handoff prior to 10 DME northwest of lax. Moorpark and woodland radar were busy at the time and getting busier. The tag drops off moorpark's and woodland's displays at about 8-10 mi northwest of lax. I, via automation, attempt to find out who the target (primary) is on V23 near chaty intersection. X tag is in my coast list. I call X and no response. The intermittent beacon return on V23 approaching twine intersection is XX07 code that belongs to an air carrier off san to las. I call X again and no response. Sector 4 calls and asks if I want higher altitude for X approaching casta. I ask woodland to call X, and X responds, X is turned southwest and issue climb instructions. As X turns, his beacon returns on code XX17. After discussing this with the lax area they had a solid XX17 transponder return until well northwest of twine where they canceled their track. ZLA sector 4 had solid transponder. The bur ASR9 has known secondary radar blind spots, ie, bur (ASR9 site) 230-285 degrees beyond 10 mi 3000 ft MSL to 9500 ft MSL on 10-20 percent of the aircraft proceeding toward vny VOR (on the antenna). These aircraft are displayed 'loud and clear' on the lax north and south ASR 9's. There are serious problems in the ASR-9 at bur that the controller is forced to work with. Callback conversation with reporter revealed the following information: reporter admitted forgetting air carrier X until reminded by another position that had air carrier X displayed on radar scope. Reporter stated this problem has been ongoing from the time the ASR-9 was installed at bur. 2 maintenance tiger teams have looked at the problem and have been unable to solve. Controllers have learned if they turn the aircraft 20 degrees left or right, the data tag will stay with the target.

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Original NASA ASRS Text

Title: ATC EQUIP PROB RADAR ASR-9 DATA TAG DROP.

Narrative: I WAS WORKING MOORPARK RADAR AND RECEIVED A HDOF FROM WOODLAND SECTOR ON ACR X NEAR SMO HDG TO JOIN V23. I HANDED X OFF TO ZLA SECTOR 4 (VIA AUTOMATION) AND THEY ACCEPTED THE HDOF PRIOR TO 10 DME NW OF LAX. MOORPARK AND WOODLAND RADAR WERE BUSY AT THE TIME AND GETTING BUSIER. THE TAG DROPS OFF MOORPARK'S AND WOODLAND'S DISPLAYS AT ABOUT 8-10 MI NW OF LAX. I, VIA AUTOMATION, ATTEMPT TO FIND OUT WHO THE TARGET (PRIMARY) IS ON V23 NEAR CHATY INTXN. X TAG IS IN MY COAST LIST. I CALL X AND NO RESPONSE. THE INTERMITTENT BEACON RETURN ON V23 APCHING TWINE INTXN IS XX07 CODE THAT BELONGS TO AN ACR OFF SAN TO LAS. I CALL X AGAIN AND NO RESPONSE. SECTOR 4 CALLS AND ASKS IF I WANT HIGHER ALT FOR X APCHING CASTA. I ASK WOODLAND TO CALL X, AND X RESPONDS, X IS TURNED SW AND ISSUE CLB INSTRUCTIONS. AS X TURNS, HIS BEACON RETURNS ON CODE XX17. AFTER DISCUSSING THIS WITH THE LAX AREA THEY HAD A SOLID XX17 XPONDER RETURN UNTIL WELL NW OF TWINE WHERE THEY CANCELED THEIR TRACK. ZLA SECTOR 4 HAD SOLID XPONDER. THE BUR ASR9 HAS KNOWN SECONDARY RADAR BLIND SPOTS, IE, BUR (ASR9 SITE) 230-285 DEGS BEYOND 10 MI 3000 FT MSL TO 9500 FT MSL ON 10-20 PERCENT OF THE ACFT PROCEEDING TOWARD VNY VOR (ON THE ANTENNA). THESE ACFT ARE DISPLAYED 'LOUD AND CLR' ON THE LAX N AND S ASR 9'S. THERE ARE SERIOUS PROBS IN THE ASR-9 AT BUR THAT THE CTLR IS FORCED TO WORK WITH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADMITTED FORGETTING ACR X UNTIL REMINDED BY ANOTHER POS THAT HAD ACR X DISPLAYED ON RADAR SCOPE. RPTR STATED THIS PROB HAS BEEN ONGOING FROM THE TIME THE ASR-9 WAS INSTALLED AT BUR. 2 MAINT TIGER TEAMS HAVE LOOKED AT THE PROB AND HAVE BEEN UNABLE TO SOLVE. CTLRS HAVE LEARNED IF THEY TURN THE ACFT 20 DEGS L OR R, THE DATA TAG WILL STAY WITH THE TARGET.

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.