Narrative:

After releasing jumpers at 12000 ft MSL, I began my typical descent over osage city airport (140 KTS, 45-60 degrees banked spiral). I was in contact with an aircraft inbound to 53K and announced jumpers were clear and my location and altitude. I also announced to ZKC that jumpers were clear. As I descended below 6000 ft I noticed another aircraft in level flight approaching from the southwest, approximately 200-300 ft below me and converging on me. I steepened my right banking turn to avoid this aircraft. The other aircraft also turned right to avoid my aircraft. After this encounter, I approached the aircraft from behind and to the right to acquire the n-number. I idented the other aircraft. I made several attempts to contact this aircraft on the local frequency. No contact was made and the aircraft flew northbound towards topeka. I was never alerted to this aircraft by ZKC. This aircraft flew directly over the drop zone and was not monitoring the local area (122.9). ATC never alerted me to a primary target in my area prior to the jump. There were no factors impairing my judgement or perception other than my banking turn on the descent. I feel I did everything within regulation and followed procedure. This situation could have been prevented if the other aircraft was monitoring the local frequency and if ATC would have told me of an aircraft in proximity of the drop zone.

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Original NASA ASRS Text

Title: A C182 PLT HAS AN NMAC DURING A SPIRALING DSCNT AFTER 'JUMPERS AWAY' WITH AN UNKNOWN C172 WHO WAS NOT ON THE LCL CTAF OR ATC CTR FREQ.

Narrative: AFTER RELEASING JUMPERS AT 12000 FT MSL, I BEGAN MY TYPICAL DSCNT OVER OSAGE CITY ARPT (140 KTS, 45-60 DEGS BANKED SPIRAL). I WAS IN CONTACT WITH AN ACFT INBOUND TO 53K AND ANNOUNCED JUMPERS WERE CLR AND MY LOCATION AND ALT. I ALSO ANNOUNCED TO ZKC THAT JUMPERS WERE CLR. AS I DSNDED BELOW 6000 FT I NOTICED ANOTHER ACFT IN LEVEL FLT APCHING FROM THE SW, APPROX 200-300 FT BELOW ME AND CONVERGING ON ME. I STEEPENED MY R BANKING TURN TO AVOID THIS ACFT. THE OTHER ACFT ALSO TURNED R TO AVOID MY ACFT. AFTER THIS ENCOUNTER, I APCHED THE ACFT FROM BEHIND AND TO THE R TO ACQUIRE THE N-NUMBER. I IDENTED THE OTHER ACFT. I MADE SEVERAL ATTEMPTS TO CONTACT THIS ACFT ON THE LCL FREQ. NO CONTACT WAS MADE AND THE ACFT FLEW NBOUND TOWARDS TOPEKA. I WAS NEVER ALERTED TO THIS ACFT BY ZKC. THIS ACFT FLEW DIRECTLY OVER THE DROP ZONE AND WAS NOT MONITORING THE LCL AREA (122.9). ATC NEVER ALERTED ME TO A PRIMARY TARGET IN MY AREA PRIOR TO THE JUMP. THERE WERE NO FACTORS IMPAIRING MY JUDGEMENT OR PERCEPTION OTHER THAN MY BANKING TURN ON THE DSCNT. I FEEL I DID EVERYTHING WITHIN REG AND FOLLOWED PROC. THIS SIT COULD HAVE BEEN PREVENTED IF THE OTHER ACFT WAS MONITORING THE LCL FREQ AND IF ATC WOULD HAVE TOLD ME OF AN ACFT IN PROX OF THE DROP ZONE.

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.