On instrument approach, air carrier has less than standard separation.

Attributes
ACN	309762
Time
Date	199507
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : spn
State Reference	FO
Altitude	msl bound lower : 1600 msl bound upper : 1700
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tower : spn
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	other : unknown
Flight Phase	descent : approach
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : cfi
Experience	flight time last 90 days : 225 flight time total : 20390 flight time type : 3500
ASRS Report	309762
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 600 vertical : 0
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Apparent inaccurate position reporting on the part of the conflicting aircraft to spn tower. Also, I suspect that the conflicting aircraft's transponder was inappropriately armed in order to affect TCASII detection by our aircraft. Conflicting aircraft was asked its position by spn tower. '5.8 DME' was the reply, as I recall. We were arriving at 6 DME. My first officer then was the first of us to get a visual on other aircraft. The so was next to get a visual on him. Conflicting aircraft was at co-altitude and converging. A left turn away from the convergence was initiated by our flight. I was trying to get TCASII advisory of the conflicting aircraft. Our TCASII was properly armed in TA/RA mode. WX radar was being used by us. I did get a primary target on the screen without an RA or a TA. By this time I had a good visual contact with converging aircraft. A diverging condition had by this time been established. Our approach, landing, and parking was then routinely completed. Conflicting aircraft made a r-hand 360 degree turn in order to complete his approach and landing as #2. Our flight was properly cleared for an instrument approach.

Original NASA ASRS Text

Title: ON INST APCH, ACR HAS LTSS.

Narrative: APPARENT INACCURATE POS RPTING ON THE PART OF THE CONFLICTING ACFT TO SPN TWR. ALSO, I SUSPECT THAT THE CONFLICTING ACFT'S XPONDER WAS INAPPROPRIATELY ARMED IN ORDER TO AFFECT TCASII DETECTION BY OUR ACFT. CONFLICTING ACFT WAS ASKED ITS POS BY SPN TWR. '5.8 DME' WAS THE REPLY, AS I RECALL. WE WERE ARRIVING AT 6 DME. MY FO THEN WAS THE FIRST OF US TO GET A VISUAL ON OTHER ACFT. THE SO WAS NEXT TO GET A VISUAL ON HIM. CONFLICTING ACFT WAS AT CO-ALT AND CONVERGING. A L TURN AWAY FROM THE CONVERGENCE WAS INITIATED BY OUR FLT. I WAS TRYING TO GET TCASII ADVISORY OF THE CONFLICTING ACFT. OUR TCASII WAS PROPERLY ARMED IN TA/RA MODE. WX RADAR WAS BEING USED BY US. I DID GET A PRIMARY TARGET ON THE SCREEN WITHOUT AN RA OR A TA. BY THIS TIME I HAD A GOOD VISUAL CONTACT WITH CONVERGING ACFT. A DIVERGING CONDITION HAD BY THIS TIME BEEN ESTABLISHED. OUR APCH, LNDG, AND PARKING WAS THEN ROUTINELY COMPLETED. CONFLICTING ACFT MADE A R-HAND 360 DEG TURN IN ORDER TO COMPLETE HIS APCH AND LNDG AS #2. OUR FLT WAS PROPERLY CLRED FOR AN INST APCH.

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.