NTSB Probable Cause

CONTINUED FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS BY A NON-INSTRUMENT RATED PILOT RESULTING IN SPATIAL DISORIENTATION AND A LOSS OF AIRCRAFT CONTROL. FACTORS CONTRIBUTING TO THE ACCIDENT WERE: THE PILOT'S OVERCONFIDENCE IN HIS ABILITY TO FLY IN INSTRUMENT CONDITIONS, THE ADVERSE WEATHER CONDITIONS, THE DARK NIGHT, AND THE PILOT'S LACK OF NIGHT FLYING EXPERIENCE.