Narrative:

We were descending on a 340 degree heading for approach to ksus. Stl approach called opposing traffic at our 11 O'clock, 5 mi, sebnd, altitude unknown. Approximately 1 min later I saw an aircraft (sel, low wing, retractable gear, white or type) at my 12 O'clock, slightly high, head on at a distance of about 500-800'. I immediately banked left and the other aircraft passed to our right within an estimated 200-300'. I believe that ATC, myself and the pilot in the other plane were acting in accordance with all applicable rules and regulations for the existing conditions. I believe the incident could have been avoided had we each taken one additional action. The pilot of the small plane would have been aware of us if he had been talking to stl approach. He wasn't within the TCA but it would have been good operating procedure to talk with approach since he was so close to the TCA. We might have been able to spot the conflicting traffic sooner had approach control given us a second callout, assuming approach had time to do so. Just prior to the incident, I had asked the copilot to find out the present location of the opposing traffic. If I had asked approach control, after his first call, for a vector to avoid traffic, we would have probably passed well clear of the other aircraft. I will be using the above procedure on future flts when ATC calls out conflicting traffic at an unknown altitude. An near midair collision report was filed through stl approach control to the FAA.

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Original NASA ASRS Text

Title: NMAC.

Narrative: WE WERE DSNDING ON A 340 DEG HDG FOR APCH TO KSUS. STL APCH CALLED OPPOSING TFC AT OUR 11 O'CLOCK, 5 MI, SEBND, ALT UNKNOWN. APPROX 1 MIN LATER I SAW AN ACFT (SEL, LOW WING, RETRACTABLE GEAR, WHITE OR TYPE) AT MY 12 O'CLOCK, SLIGHTLY HIGH, HEAD ON AT A DISTANCE OF ABOUT 500-800'. I IMMEDIATELY BANKED LEFT AND THE OTHER ACFT PASSED TO OUR RIGHT WITHIN AN ESTIMATED 200-300'. I BELIEVE THAT ATC, MYSELF AND THE PLT IN THE OTHER PLANE WERE ACTING IN ACCORDANCE WITH ALL APPLICABLE RULES AND REGS FOR THE EXISTING CONDITIONS. I BELIEVE THE INCIDENT COULD HAVE BEEN AVOIDED HAD WE EACH TAKEN ONE ADDITIONAL ACTION. THE PLT OF THE SMALL PLANE WOULD HAVE BEEN AWARE OF US IF HE HAD BEEN TALKING TO STL APCH. HE WASN'T WITHIN THE TCA BUT IT WOULD HAVE BEEN GOOD OPERATING PROC TO TALK WITH APCH SINCE HE WAS SO CLOSE TO THE TCA. WE MIGHT HAVE BEEN ABLE TO SPOT THE CONFLICTING TFC SOONER HAD APCH CTL GIVEN US A SECOND CALLOUT, ASSUMING APCH HAD TIME TO DO SO. JUST PRIOR TO THE INCIDENT, I HAD ASKED THE COPLT TO FIND OUT THE PRESENT LOCATION OF THE OPPOSING TFC. IF I HAD ASKED APCH CTL, AFTER HIS FIRST CALL, FOR A VECTOR TO AVOID TFC, WE WOULD HAVE PROBABLY PASSED WELL CLR OF THE OTHER ACFT. I WILL BE USING THE ABOVE PROC ON FUTURE FLTS WHEN ATC CALLS OUT CONFLICTING TFC AT AN UNKNOWN ALT. AN NMAC RPT WAS FILED THROUGH STL APCH CTL TO THE FAA.

Data retrieved from NASA's ASRS site as of August 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.