Northeast Airlines Flight 792 originated at Boston, Massachusetts, for Berlin, New Hampshire, with stops at Concord and Laconia, New Hampshire. Departure from Laconia was on schedule at 10:39. The IFR flight proceeded at a cruising altitude of 8000 feet towards Berlin. At 11:03 the flight called the company station at the Berlin Airport and asked for local weather. The station agent immediately gave the 10:45 observation: Estimated 3,000 feet overcast; visibility 2-1/2 miles; light snow showers. The agent then made a special weather observation at 11:10 which added scattered clouds at 2,300 feet to the previous weather information. Airport minimums at Berlin were a 2,300 ft ceiling and 2 miles visibility. This information was acknowledged by the crew. Meanwhile the flight was descending to get beneath the overcast for a straight-in approach. The captain was able to recognize visual references on the ground until the moment the flight entered overcast. The airplane impacted the snow-covered southern slope of Mount Success, 100 feet below the top, at an elevation of 3,440 feet. PROBABLE CAUSE: “A pre-mature and unauthorized instrument descent to an altitude that did not permit terrain clearance..”