THE PLT STATED THAT THIS WAS NOT A CHARTER FLT AND, AS SUCH, HE DECIDED TO ATTEMPT THE LOC 17 APCH TO OLATHE EVEN THOUGH THE AREA WAS FORECASTING ZERO-ZERO CONDITIONS. ACCORDING TO THE PLT, THE LAST THING HE REMEMBERS DURING THE FLT IS BRACKETING THE LOC AND READING 1,600 FT ON THE ALTIMETER.SUBSEQUENTLY, THE PLT FURTHER STATED, HE REMEMBERS BEING ON THE GROUND INSIDE THE WRECKAGE, MITIGATING THE INJURIES SUFFERED AND TRYING TO STAY WARM. A POST-ACCIDENT INVEST REVEALED THAT THE ACFT WAS TO THE LEFT OF THE LOCALIZER COURSE WHEN IT STRUCK TWO TREES 12 FT AGL (1,062 FT MSL), WHILE IN A 30 DEG RIGHT BANK. THE ACFT MADE A FLAT 360 RIGHT PIROUETTE OVER SOME SMALL TREES, TEARING OFF THE LEFT WING BEFORE IMPACTING THE GRND AND SLIDING APRX 600 FT. A POST-CRASH FIRE ERUPTED FROM THE RIGHT WING TANK BUT IT EXTINGUISHED ITSELF. A DOT FAA OPERATIONAL FLT TEST FOUND THE LOCALIZER TO BE WITHIN LIMITS. A LEAK CHECK OF THE ACFT STATIC SYSTEM AND A BENCH CHECK OF BOTH ALTIMETERS WERE SATISFACTORY.