Airborne conflict between small transport X and air carrier Y in TCA. See and avoid.

Attributes
ACN	133859
Time
Date	199001
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : stl
State Reference	MO
Altitude	msl bound lower : 3750 msl bound upper : 3750
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : stl
Operator	general aviation : corporate
Make Model Name	Small Transport
Flight Phase	descent other
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent : approach
Route In Use	approach : visual enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 75 flight time total : 6885 flight time type : 2000
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted other
Consequence	Other
Miss Distance	horizontal : 0 vertical : 1000
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Small transport X was arriving at lambert field (stl) from the northwest on the atlas 5 arrival. In visual conditions approach had us turn right to 190 degree and maintain 6000' to put us on an intercept for runway 126. Approach asked if we saw traffic being vectored for runway 12R. We responded negatively. Then approach cleared us to 4500' and left to 150 degree. They asked if we had the runway 12R traffic. I said we did not but we did have the airport. A few seconds later I did respond that we had traffic low, inside the missouri river on final for runway 12R. Approach said that was the traffic. They then said, 'keep the traffic in sight' and cleared us for visual runway 12L. We replied. After we were established on final for runway 12L and I am estimating 3750' MSL high and 4.5 mi from the end of the runway an air carrier Y crossed our flight path at 90 degree to us from left to right. He went underneath us and then turned 90 degree to the left to put himself on final for runway 12R. By this time we were talking to stl tower and asked where the air carrier that went underneath us was going. They said for runway 12R. (There are separate frequencys for 12L and 12R). After landing the tower asked if approach had told us about the traffic. We said no, but we had acknowledged other traffic. The traffic conflict was not so close that we had to take evasive action. However, it was surprising to me that approach would let a large aircraft cut across our final approach path like that. The conflict was not as bad as it could have been because we were higher than normal for our approach point plus we picked him up before we went over him.

Original NASA ASRS Text

Title: AIRBORNE CONFLICT BETWEEN SMT X AND ACR Y IN TCA. SEE AND AVOID.

Narrative: SMT X WAS ARRIVING AT LAMBERT FIELD (STL) FROM THE NW ON THE ATLAS 5 ARR. IN VISUAL CONDITIONS APCH HAD US TURN RIGHT TO 190 DEG AND MAINTAIN 6000' TO PUT US ON AN INTERCEPT FOR RWY 126. APCH ASKED IF WE SAW TFC BEING VECTORED FOR RWY 12R. WE RESPONDED NEGATIVELY. THEN APCH CLRED US TO 4500' AND LEFT TO 150 DEG. THEY ASKED IF WE HAD THE RWY 12R TFC. I SAID WE DID NOT BUT WE DID HAVE THE ARPT. A FEW SECONDS LATER I DID RESPOND THAT WE HAD TFC LOW, INSIDE THE MISSOURI RIVER ON FINAL FOR RWY 12R. APCH SAID THAT WAS THE TFC. THEY THEN SAID, 'KEEP THE TFC IN SIGHT' AND CLRED US FOR VISUAL RWY 12L. WE REPLIED. AFTER WE WERE ESTABLISHED ON FINAL FOR RWY 12L AND I AM ESTIMATING 3750' MSL HIGH AND 4.5 MI FROM THE END OF THE RWY AN ACR Y CROSSED OUR FLT PATH AT 90 DEG TO US FROM LEFT TO RIGHT. HE WENT UNDERNEATH US AND THEN TURNED 90 DEG TO THE LEFT TO PUT HIMSELF ON FINAL FOR RWY 12R. BY THIS TIME WE WERE TALKING TO STL TWR AND ASKED WHERE THE ACR THAT WENT UNDERNEATH US WAS GOING. THEY SAID FOR RWY 12R. (THERE ARE SEPARATE FREQS FOR 12L AND 12R). AFTER LNDG THE TWR ASKED IF APCH HAD TOLD US ABOUT THE TFC. WE SAID NO, BUT WE HAD ACKNOWLEDGED OTHER TFC. THE TFC CONFLICT WAS NOT SO CLOSE THAT WE HAD TO TAKE EVASIVE ACTION. HOWEVER, IT WAS SURPRISING TO ME THAT APCH WOULD LET A LARGE ACFT CUT ACROSS OUR FINAL APCH PATH LIKE THAT. THE CONFLICT WAS NOT AS BAD AS IT COULD HAVE BEEN BECAUSE WE WERE HIGHER THAN NORMAL FOR OUR APCH POINT PLUS WE PICKED HIM UP BEFORE WE WENT OVER HIM.

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.