BFR RCHG HIS DESTN, THE PLT ADZD APCH CTL THAT HIS RGT ENG WAS 'BLOWING SOME SMOKE' & LOSING OIL PRESSURE. VECTORS WERE PROVIDED FOR A VISUAL APCH, BUT THERE WERE LOW CLOUDS IN THE AREA & VIS WAS RESTRICTED DUE TO HAZE. AFTER REACHING THE VCNTY OF THE ARPT, THE PLT SAID IT WAS IN SIGHT & HE WAS ENTERING A DOWNWIND FOR RWY 30. WITNESSES SAW THE ACFT ON A LEFT DOWNWIND, BUT SAID THE ACFT OVERSHOT THE 1ST TURN TO FINAL APCH. SUBSEQUENTLY, WHILE MANEUVERING TO LAND, THE ACFT CRASHED APRX 2500' NE OF THE RWY IN A WOODED AREA. WITNESSES AGREED THE ACFT WAS SLOW & IN A STEEP RGT TURN WITH THE GEAR EXTD BFR IT CRASHED IN A STEEP DSCNT & BURNED. AN EXAM REVEALED EVIDENCE THE STARTER ON THE RGT ENG HAD BACKED OFF; 3 STARTER BOLTS HAD FRACTURED THRU THE THREADED AREA WITH SIGNS OF FATIGUE CRACKING; WEAR MARKS ON THE STARTER GEAR & ENG GEAR RING INDCD THE STARTER MOTOR HAD SHIFTED APRX 3/4' REARWARD. ALSO, THERE WAS EVIDENCE THE TORSIONAL DAMPER WAS LOOSE ON ITS SHAFT BFR THE ACDNT & THAT BOTH PROPS WERE OPERG AT LOW PITCH DRG INITIAL IMPACT.