THE PILOT ATTEMPTED A NIGHT SPECIAL VFR APPROACH TO THE AIRPORT WHEN HE WAS NOT NIGHT CURRENT. HE DID NOT HOLD AN INSTRUMENT RATING. THE PILOT OBTAINED THREE WEATHER REPORTS FOR THE AIRPORT, WHILE EN ROUTE. THESE ESTABLISHED THAT CONDITIONS WERE IFR WITH VISIBILITIES LESS THAN 2 MILES IN FOG. THE PILOT ACCEPTED THE SPECIAL VFR CLEARANCE AND REPORTED INBOUND TO THE AIRPORT FROM THE NORTH. SHORTLY THEREAFTER, HE REPORTED OVER A PRISON, WHICH WAS 4 MILES NORTH EAST OF THE AIRPORT. THE PRISONERS SAID THE AIRCRAFT ORBITED ONE OF THE GUARD TOWERS TWO OR THREE TIMES, THEN DEPARTED TO THE NORTH WEST. THE OFFICIAL VISIBILITY REPORTED BY THE ATCT WAS ONE MILE IN FOG; WITNESSES AT THE PRISON STATED THE GROUND VISIBILITY WAS LESS THAN A MILE WITH AREAS OF HEAVY FOG. THE AIRCRAFT COLLIDED WITH THE GROUND IN A DESCENT MEASURED AT 11 DEGREES WITH A RIGHT WING DOWN ABOUT 20 DEGREES. NO PREIMPACT MECHANICAL MALFUNCTIONS OR FAILURES WERE IDENTIFIED DURING EXAMINATION OF THE WRECKAGE.