Aircraft misid on radar.

Attributes
ACN	294838
Time
Date	199501
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : msp
State Reference	MN
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : geg
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : msp
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 190 flight time total : 18000 flight time type : 190
ASRS Report	294838
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

We were approaching msp, flying the STAR (nickl 2 with brb transition). We were heading west. The controller suddenly instructed us to turn 10 degrees right and re-intercept the arrival. We were startled, because our 2 RNAV displays showed us to be exactly on the arrival. Thus we couldn't comply with both parts of the controller's direction, since a turn would take us away from the arrival, and we would never re-intercept. I asked her where she showed our position, and I told her we were concerned because we showed on course with our cockpit displays. She replied that she showed us 7 mi north of course and repeated the command to turn, this time with irritation. That made even less sense, because if we were north of course and turned right, we would get farther away. Meanwhile we crosschecked the raw VOR data, and it agreed with the RNAV. I told her I was confused about what she wanted, and she replied that we should go direct to the next intersection. She was busy with traffic, so we did so and said no more. Perhaps she thought we were arriving from mke rather than grb. That would explain the 7 mi north, but a right turn would still be wrong. Perhaps the controller's map is in error, for I have heard controllers tell several other aircraft that they were off course in that area.

Original NASA ASRS Text

Title: ACFT MISID ON RADAR.

Narrative: WE WERE APCHING MSP, FLYING THE STAR (NICKL 2 WITH BRB TRANSITION). WE WERE HDG W. THE CTLR SUDDENLY INSTRUCTED US TO TURN 10 DEGS R AND RE-INTERCEPT THE ARR. WE WERE STARTLED, BECAUSE OUR 2 RNAV DISPLAYS SHOWED US TO BE EXACTLY ON THE ARR. THUS WE COULDN'T COMPLY WITH BOTH PARTS OF THE CTLR'S DIRECTION, SINCE A TURN WOULD TAKE US AWAY FROM THE ARR, AND WE WOULD NEVER RE-INTERCEPT. I ASKED HER WHERE SHE SHOWED OUR POS, AND I TOLD HER WE WERE CONCERNED BECAUSE WE SHOWED ON COURSE WITH OUR COCKPIT DISPLAYS. SHE REPLIED THAT SHE SHOWED US 7 MI N OF COURSE AND REPEATED THE COMMAND TO TURN, THIS TIME WITH IRRITATION. THAT MADE EVEN LESS SENSE, BECAUSE IF WE WERE N OF COURSE AND TURNED R, WE WOULD GET FARTHER AWAY. MEANWHILE WE XCHKED THE RAW VOR DATA, AND IT AGREED WITH THE RNAV. I TOLD HER I WAS CONFUSED ABOUT WHAT SHE WANTED, AND SHE REPLIED THAT WE SHOULD GO DIRECT TO THE NEXT INTXN. SHE WAS BUSY WITH TFC, SO WE DID SO AND SAID NO MORE. PERHAPS SHE THOUGHT WE WERE ARRIVING FROM MKE RATHER THAN GRB. THAT WOULD EXPLAIN THE 7 MI N, BUT A R TURN WOULD STILL BE WRONG. PERHAPS THE CTLR'S MAP IS IN ERROR, FOR I HAVE HEARD CTLRS TELL SEVERAL OTHER ACFT THAT THEY WERE OFF COURSE IN THAT AREA.

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.