Multiple runway operation parallel approachs radar equipment problem ASR-9 data tag drop.

Attributes
ACN	244505
Time
Date	199306
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : stl
State Reference	MO
Altitude	msl bound lower : 2500 msl bound upper : 5500
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : stl
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 10
ASRS Report	244505
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 final monitor, approachs were in progress to runway 12L via the lda and runway 12R via the ILS. On 10 separate occasions in a 30 min period, I noticed the ARTS data block drop off the primary targets. After 2-4 sweeps it would get back on the primary target it was associated with. This all happened on the runway 12L lda between steph and jamie. I brought this to the attention of my supervisor. He changed channels on the radar but the problem persisted. I should also mention all aircraft were staggered by about 1 mi from the aircraft they were paired with on the runway 12R ILS and the runway 12R aircraft was in the lead.

Original NASA ASRS Text

Title: MULTIPLE RWY OP PARALLEL APCHS RADAR EQUIP PROB ASR-9 DATA TAG DROP.

Narrative: I WAS WORKING FINAL MONITOR, APCHS WERE IN PROGRESS TO RWY 12L VIA THE LDA AND RWY 12R VIA THE ILS. ON 10 SEPARATE OCCASIONS IN A 30 MIN PERIOD, I NOTICED THE ARTS DATA BLOCK DROP OFF THE PRIMARY TARGETS. AFTER 2-4 SWEEPS IT WOULD GET BACK ON THE PRIMARY TARGET IT WAS ASSOCIATED WITH. THIS ALL HAPPENED ON THE RWY 12L LDA BTWN STEPH AND JAMIE. I BROUGHT THIS TO THE ATTN OF MY SUPVR. HE CHANGED CHANNELS ON THE RADAR BUT THE PROB PERSISTED. I SHOULD ALSO MENTION ALL ACFT WERE STAGGERED BY ABOUT 1 MI FROM THE ACFT THEY WERE PAIRED WITH ON THE RWY 12R ILS AND THE RWY 12R ACFT WAS IN THE LEAD.

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.