ASR-9 ATC equipment problem radar data tag and primary target jump.

Attributes
ACN	273389
Time
Date	199406
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : sjt
State Reference	TX
Altitude	msl bound lower : 3500 msl bound upper : 3500
Environment
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : maf
Operator	other
Make Model Name	Military Trainer
Operating Under FAR Part	Part 91
Navigation In Use	Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 5
ASRS Report	273389
Person 2
Affiliation	government : military
Function	flight crew : single pilot
Qualification	pilot : military
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other

Narrative:

I was working military X, a T-1, on a surveillance approach to runway 18 at sjt. The aircraft was on a 5 mi final when the tag jumped off the final quickly followed by the primary. As I reached for my microphone button (thinking the aircraft was beginning to stray) the tag and primary returned to the earlier course only now at 4 3/4 mi. Again at 4 mi and again at 3 mi the tag and primary jumped off the course. My fellow controller next to me noticed the last 2 jumps. Evidently there is an update problem with the ASR-9 antennae and/or the relays used to remote it to midland.

Original NASA ASRS Text

Title: ASR-9 ATC EQUIP PROB RADAR DATA TAG AND PRIMARY TARGET JUMP.

Narrative: I WAS WORKING MIL X, A T-1, ON A SURVEILLANCE APCH TO RWY 18 AT SJT. THE ACFT WAS ON A 5 MI FINAL WHEN THE TAG JUMPED OFF THE FINAL QUICKLY FOLLOWED BY THE PRIMARY. AS I REACHED FOR MY MIKE BUTTON (THINKING THE ACFT WAS BEGINNING TO STRAY) THE TAG AND PRIMARY RETURNED TO THE EARLIER COURSE ONLY NOW AT 4 3/4 MI. AGAIN AT 4 MI AND AGAIN AT 3 MI THE TAG AND PRIMARY JUMPED OFF THE COURSE. MY FELLOW CTLR NEXT TO ME NOTICED THE LAST 2 JUMPS. EVIDENTLY THERE IS AN UPDATE PROB WITH THE ASR-9 ANTENNAE AND/OR THE RELAYS USED TO REMOTE IT TO MIDLAND.

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.