NMAC OCCURRED BTWN A C210 AND A TH57 AT A NON TWR ARPT. THE INBOUND C210 PLT HEARD THE OUTBOUND MIL HELI ANNOUNCE THE MAP PRIOR TO THE CONFLICT.

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I BELIEVE THE PROB AROSE DUE TO HVY MIL HELI TRAINING ACTIVITY AT THE CRESTVIEW; BOB SIKES ARPT. THE ARPT HAS A SINGLE RWY 17/35 WITH VOR-A; NDB RWY 17; AND LOC RWY 17 APCHS. THE NAVY TH57 WAS ON A MAP FROM RWY 17; HOWEVER THE 'ACTIVE' RWY WAS RWY 35 DUE TO FAVORABLE WINDS. I HAD JUST CALLED CRESTVIEW RADIO (FSS) FOR AN ADVISORY COMING IN FROM ABOUT 10 MI E. THEY ADVISED RWY 35 IN USE; HOWEVER; I WASN'T ADVISED OF THE OUTBOUND TO THE E; A TH57 ON A MAP. I ONLY KNEW ABOUT IT FROM MONITORING THE CTAF FOR A FEW MINS BEFORE INITIAL CALL UP. THE TH57 WAS ALREADY HANDED OFF TO EGLIN APCH WHEN THE CONFLICT AROSE. SO WE HAVE A SIT: A MIL HELI DOING INST TRAINING AND AN INBOUND FIXED WING; BOTH ON DIFFERENT FREQS. I BELIEVE THE HELI WAS AT 2000 FT MSL WHEN I PASSED BELOW ON MY DSCNT FOR THE TFC PATTERN OF 1200 FT MSL. THE HELI WAS STILL FAIRLY CLOSE TO THE ARPT. SO I THINK THEY SHOULD HAVE BEEN MONITORING CTAF ON #2. ANOTHER PROB CAME WHEN I HEARD THE HELI ANNOUNCE ON CTAF HE WAS EXECUTING THE MAP AND CRESTVIEW RADIO ADVISED HIM TO CONTACT EGLIN APCH. THE PLT DIDN'T MENTION TO OTHERS INBOUND WHAT THOSE INSTRUCTIONS WERE; THAT IS 'EBOUND TO 2000 FT;' OR SOMETHING LIKE THAT. THE CEW VORTAC IS TO THE W SO THAT WAS WHERE I ASSUMED HE WAS GOING. ANOTHER CONTRIBUTING FACTOR WAS THE FACT I WAS GOING DUE W INTO THE LATE AFTERNOON SUN FOR A XWIND ENTRY TO THE PATTERN FOR RWY 35.