Controller complaint about data tag FLIP flop on parallel approach aircraft.

Attributes
ACN	210635
Time
Date	199205
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : stl
State Reference	MO
Aircraft 1
Controlling Facilities	tracon : stl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	other personnel other
Qualification	controller : radar
ASRS Report	210635
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other
Situations
ATC Facility	other physical facility

Narrative:

In an ongoing effort to keep you abreast of the problems at stl are encountering with our ASR9 radar let me really to you what I observed yesterday, 5/X/92, as I worked the final monitor position. We were running simultaneous approachs to 12L and 12R via the 12L lda localizer and the 12R ILS localizer. Air carrier X was on the lda localizer paired with air carrier Y on the ILS localizer. They were 11 mi from lambert airport. Air carrier Y's primary jumped up about 1/2 mi behind air carrier X's primary target. One sweep later it was correctly repositioned on the 12 localizer. In talking with 2 controllers who worked the position later in the day they stated that they also observed similar scenarios. This situation should not happen ever. If you read the enclosed notice (stl ATCT N7110.123) the procedures instituted 'will eliminate these occurrences.'

Original NASA ASRS Text

Title: CTLR COMPLAINT ABOUT DATA TAG FLIP FLOP ON PARALLEL APCH ACFT.

Narrative: IN AN ONGOING EFFORT TO KEEP YOU ABREAST OF THE PROBLEMS AT STL ARE ENCOUNTERING WITH OUR ASR9 RADAR LET ME REALLY TO YOU WHAT I OBSERVED YESTERDAY, 5/X/92, AS I WORKED THE FINAL MONITOR POS. WE WERE RUNNING SIMULTANEOUS APCHS TO 12L AND 12R VIA THE 12L LDA LOC AND THE 12R ILS LOC. ACR X WAS ON THE LDA LOC PAIRED WITH ACR Y ON THE ILS LOC. THEY WERE 11 MI FROM LAMBERT ARPT. ACR Y'S PRIMARY JUMPED UP ABOUT 1/2 MI BEHIND ACR X'S PRIMARY TARGET. ONE SWEEP LATER IT WAS CORRECTLY REPOSITIONED ON THE 12 LOC. IN TALKING WITH 2 CTLRS WHO WORKED THE POS LATER IN THE DAY THEY STATED THAT THEY ALSO OBSERVED SIMILAR SCENARIOS. THIS SITUATION SHOULD NOT HAPPEN EVER. IF YOU READ THE ENCLOSED NOTICE (STL ATCT N7110.123) THE PROCS INSTITUTED 'WILL ELIMINATE THESE OCCURRENCES.'

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.