AFTER THE PLT WAS CLEARED FOR AN RNAV-B APCH, THE ACFT CRASHED ON HILLY TRRN APRX 3 MI SE OF THE ARPT AT AN ELEV OF 750'MSL. IMPACT OCCURRED AFTER THE ACFT HAD TURNED TO THE SSE & WAS DSCNDG. MIN DSCNT ALT (MDA) FOR THE APCH WAS 1680'. NO PREIMPACT MECHANICAL PROBLEMS WERE FND. APRX 4 HRS BFR TAKEOFF, FSS PSNL PROVIDED A WX BRIEFING. THERE WAS NO WX RPRTG STN AT THE DESTN, BUT THE AREA FORECAST WAS FOR MARGINAL VMC WITH ISOLATED VISIBILITIES OF 3 TO 5 MI IN LGT SNW SHOWERS.PELLSTON (APRX 25 MI AWAY) WAS FORECAST FOR A CHANCE OF 1200' OVERCAST & 3 MI VIS WITH LGT SNW SHOWERS, BUT THIS INFO WAS NOT GIVEN TO THE PLT. LATER, WHEN THE PLT FILED AN IFR FLT PLAN, HE DID NOT UPDATE HIS WX BRIEFING. WHILE EN ROUTE, HE CHECKED THE PELLSTON & TRAVERSE CITY WX & WAS ADVISED THEY HAD INDEF OR OBSCD CEILINGS OF 1500' OR LESS WITH GUSTY WNDS & LGT SNW SQUALLS. ACCORDING TO WITNESSES, THERE WERE SNW SHOWERS OR SQUALLS IN THE ACDNT AREA WITH 1/4 TO 3/4 MI VIS. THE MISSED APCH PROCEDURE CALLED FOR: RGT CLIMBING TURN TO 3000', PROCEED TO THE IAF (8 MI SOUTH OF ARPT) & HOLD.