ATC equipment problem radar ASR-9.

Attributes
ACN	320542
Time
Date	199511
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : slc
State Reference	UT
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : slc
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 5
ASRS Report	320542
Person 2
Affiliation	government : faa
Function	oversight : supervisor
Qualification	controller : radar
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other
Situations
Navigational Aid	Unspecified

Narrative:

While running simultaneous approachs to runways 34L and 34R, air carrier X, a CL65, and air carrier Y, a B737, were on parallel finals. Near point at the mountain, X overtook Y when both aircraft were at 10000 ft MSL. The radar (ASR 9) merged targets for 1 to 2 sweeps and then returned them to their actual positions established on separate localizers. There was no time to break either aircraft out and in all actuality neither aircraft deviated from the localizer. A few moments later a heavy jet also passed an aircraft in the same location. The aircraft being passed stayed on its course but for 1 or 2 sweeps there was no radar return on the heavy jet. There have also been many targets 'jumping' on these final approach courses. The target jumping has been an ongoing problem with the ASR 9 at salt lake approach, but now that we are running simultaneous approachs it presents a new problem. The radar is severely limiting the controller's ability to run simultaneous approachs. Callback conversation with reporter revealed the following information: facility supervisor stated they are aware of the radar problem which is called stitching. Simultaneous approach procedures have been terminated. Maintenance told supervisor they have a fix for the problem which will be installed shortly.

Original NASA ASRS Text

Title: ATC EQUIP PROB RADAR ASR-9.

Narrative: WHILE RUNNING SIMULTANEOUS APCHS TO RWYS 34L AND 34R, ACR X, A CL65, AND ACR Y, A B737, WERE ON PARALLEL FINALS. NEAR POINT AT THE MOUNTAIN, X OVERTOOK Y WHEN BOTH ACFT WERE AT 10000 FT MSL. THE RADAR (ASR 9) MERGED TARGETS FOR 1 TO 2 SWEEPS AND THEN RETURNED THEM TO THEIR ACTUAL POSITIONS ESTABLISHED ON SEPARATE LOCALIZERS. THERE WAS NO TIME TO BREAK EITHER ACFT OUT AND IN ALL ACTUALITY NEITHER ACFT DEVIATED FROM THE LOC. A FEW MOMENTS LATER A HVY JET ALSO PASSED AN ACFT IN THE SAME LOCATION. THE ACFT BEING PASSED STAYED ON ITS COURSE BUT FOR 1 OR 2 SWEEPS THERE WAS NO RADAR RETURN ON THE HVY JET. THERE HAVE ALSO BEEN MANY TARGETS 'JUMPING' ON THESE FINAL APCH COURSES. THE TARGET JUMPING HAS BEEN AN ONGOING PROB WITH THE ASR 9 AT SALT LAKE APCH, BUT NOW THAT WE ARE RUNNING SIMULTANEOUS APCHS IT PRESENTS A NEW PROB. THE RADAR IS SEVERELY LIMITING THE CTLR'S ABILITY TO RUN SIMULTANEOUS APCHS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FACILITY SUPVR STATED THEY ARE AWARE OF THE RADAR PROB WHICH IS CALLED STITCHING. SIMULTANEOUS APCH PROCS HAVE BEEN TERMINATED. MAINT TOLD SUPVR THEY HAVE A FIX FOR THE PROB WHICH WILL BE INSTALLED SHORTLY.

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.