Track jump gets controller's attention.

Attributes
ACN	214239
Time
Date	199207
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : tbn
State Reference	MO
Altitude	msl bound lower : 6100 msl bound upper : 6800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc tower : ord
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	214239
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other

Narrative:

First of all -- no occurrence actually happened. Air carrier X, an small transport, was tbn radar vector stl climbing to 9000. Nga Y, an small aircraft, was pah foe 10000 ft descending to 6000. Nga Y was 23 NM north tbn VOR 6800. Air carrier X was 5 NM north tbn 6100 for 9000 heading D25 to intercept ftz 265 radial. A radar target jump occurred putting air carrier X's target right with nga Y 23 NM north of tbn VOR 700 ft converging altitudes. I did not observe the target jump occur until conflict alert activated. I tried to figure out what had happened and gave air carrier X a clearance to descend to 5000 ft. Air carrier X questioned the clearance. Nga Y was tracking about 300 degree and air carrier X with him was tracking about 340 degree. I questioned air carrier X's heading and wondered how he got where he was. No other radar target visible where I thought he should be. He replied heading 025 as assigned. My heart was in my throat as I was trying to determine the best way to get the 2 aircraft apart when the target on air carrier X jumped back to its original position 8 NM north of tbn diverging and 18 NM away from nga Y.

Original NASA ASRS Text

Title: TRACK JUMP GETS CTLR'S ATTN.

Narrative: FIRST OF ALL -- NO OCCURRENCE ACTUALLY HAPPENED. ACR X, AN SMT, WAS TBN RADAR VECTOR STL CLBING TO 9000. NGA Y, AN SMA, WAS PAH FOE 10000 FT DSNDING TO 6000. NGA Y WAS 23 NM N TBN VOR 6800. ACR X WAS 5 NM N TBN 6100 FOR 9000 HDG D25 TO INTERCEPT FTZ 265 RADIAL. A RADAR TARGET JUMP OCCURRED PUTTING ACR X'S TARGET RIGHT WITH NGA Y 23 NM N OF TBN VOR 700 FT CONVERGING ALTS. I DID NOT OBSERVE THE TARGET JUMP OCCUR UNTIL CONFLICT ALERT ACTIVATED. I TRIED TO FIGURE OUT WHAT HAD HAPPENED AND GAVE ACR X A CLRNC TO DSND TO 5000 FT. ACR X QUESTIONED THE CLRNC. NGA Y WAS TRACKING ABOUT 300 DEG AND ACR X WITH HIM WAS TRACKING ABOUT 340 DEG. I QUESTIONED ACR X'S HDG AND WONDERED HOW HE GOT WHERE HE WAS. NO OTHER RADAR TARGET VISIBLE WHERE I THOUGHT HE SHOULD BE. HE REPLIED HDG 025 AS ASSIGNED. MY HEART WAS IN MY THROAT AS I WAS TRYING TO DETERMINE THE BEST WAY TO GET THE 2 ACFT APART WHEN THE TARGET ON ACR X JUMPED BACK TO ITS ORIGINAL POS 8 NM N OF TBN DIVERGING AND 18 NM AWAY FROM NGA Y.

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.