THE ATP CERTIFICATED PILOT IN COMMAND DEPARTED ON A SOLO, CARGO-ONLY AIR-TAXI FLIGHT AT 1104 A.K.S.T. FOR A DESTINATION 83SM TO THE N.E. THE PILOT WAS NORMALLY ASSIGNED TO COPILOT DUTIES ON A MULTI-ENGINED AIRPLANE, AND WAS NOT FAMILIAR WITH THE TERRAIN HE WAS FLYING OVER ON THIS FLIGHT. THE AIRCRAFT STRUCK RISING TERRAIN APPROXIMATELY 40SM N.E. OF THE DEPARTURE AIRPORT AND WAS SUBSTANTIALLY DAMAGED. THE PILOT SAYS HE DOES NOT RECALL THE FLIGHT PRIOR TO THE ACCIDENT; HE SUFFERED MINOR INJURIES AND WAS KNOCKED UNCONSCIOUS DURING IMPACT. WEATHER CONDITIONS AT THE CRASH SITE ARE UNKNOWN, BUT A PILOT FLYING IN THE SAME GENERAL AREA SHORTLY AFTER THE ACCIDENT REPORTED LOCALIZED AREAS OF FOG AND SNOW THAT REDUCED VISIBILITY TO LESS THAN ONE-HALF MILE. THE PILOT WAS RECOVERED BY COAST GUARD SEARCH AND RESCUE PERSONNEL APPROXIMATELY 24 HOURS AFTER THE ACCIDENT.