THE MANAGER OF BLACKHAWK AIRWAYS HAD CLEARED THE FLT FOR A 1000 EDT DEPARTURE, BUT THE ACTUAL TAKEOFF TIME WAS NOT ESTABLISHED. NO RECORD OF A PREFLT WX BRIEFING WAS FOUND. HOWEVER, DURING A TELEPHONE CONVERSATION PRIOR TO THE FLT, THE PLT INDICATED TO HIS MANAGER THAT THE CLOUDS WOULD BE LOWER IN THE MOUNTAINS. AT APRX 1030, GROUND WITNESSES OBSERVED AN ACFT, MATCHING THE DESCRIPTION OF N215W, CIRCLING BENEATH THE CLOUDS AT KEYSER, WV, THEN DEPART TO THE SOUTHWEST. WHEN THE ACFT DID NOT ARRIVE AT ITS DESTINATION, A SEARCH WAS BEGUN. IT WAS FOUND WHERE IT HAD IMPACTED RISING TERRAIN APRX 6 MI SOUTHWEST OF KEYSER. THE IMPACT OCCURRED ON A 26 DEG SLOPE, AT APRX THE 3000 FT LEVEL, JUST BELOW A 3104 FT PEAK. THE ACFT WAS CLIMBING WHEN IT IMPACTED WOODED TERRAIN. A PLT/MECHANICAL, WHO OPERATED AN ARPT APRX 3 MI SOUTHEAST OF KEYSER, REPORTED THERE WAS FOG IN THE MORNING HRS WITH A CEILING OF ABOUT 2000 FT UNTIL MIDDAY & THAT THE MOUNTAIN TOPS IN THE VICINITY OF THE CRASH SITE WERE OBSCURED.