THE ACFT CRASHED DURING THE APPROACH TO LAND AT A FOGGED IN ARPT AT NIGHT. SOMETIME BETWEEN 2045 AND 2100 YST AN ACFT WAS HEARD OVERFLYING THE ARPT AT NUIQSUT. THE VILLAGER WHO HEARD THE ACFT STATED THE NOISE DECREASED AS THOUGH THE ACFT WAS LANDING. HE THEN HEARD A SOUND DESCRIBED AS A PIECE OF METAL ROOFING SLIDING ACROSS GRAVEL. HE THOUGHT THE ACFT HAD LANDED BUT DID NOT SEE ANY LIGHTS ON THE RWY. HE ALSO STATED HE COULD NOT SEE ACROSS THE RWY DUE TO THE FOG. ACCORDING TO THE PASSENGERS WHO FLEW OUTBOUND TO DEADHORSE WITH THIS PLT THE LIGHTS IN THE COCKPIT WERE MARGINAL AND THE PLT USED A FLASHLIGHT SOME OF THE TIME. A COUPLE OF TIMES ACCORDING TO A PASSENGER GOING TO DEADHORSE THE ACFT'DROPPED' WHEN THE PLT LOST SIGHT OF LIGHTS ON THE GROUND. THE PLT WAS ALONE ON THE RETURN TRIP. THE PLT ALSO HAD A HISTORY OF HYPERTENSIONAND WAS TAKING MEDICINE FOR HIGH BLOOD PRESSURE.