On January 23, 2000, at 1130 hours Pacific standard time, a Cessna 310F, N5801X, made a hard landing on runway 27L at the Boulder City, Nevada, airport. The airplane sustained substantial damage. The flight instructor, student pilot, and two passengers were not injured. The airplane was operated by De Voit, Inc., as an instructional flight, under 14 CFR Part 91 when the accident occurred. The flight originated at Boulder City airport approximately 30 minutes prior to the accident. Visual meteorological conditions prevailed at the time of the accident and a flight plan was not filed. According to the flight instructor, the student pilot was on final approach to the runway, and was approximately 50 feet above ground level (agl) when the flight instructor noticed that the airplane was descending much too fast. He said he told the student pilot to add power, but the student pilot only added power to the right engine. He said he noticed the airplane yaw to the left and then he took over the controls. The flight instructor said that the airplane was displaced at least a wingspan's length from the runway edge by the time he recovered the airplane. He said that he pulled the airplane back up to about 20 feet above ground level (agl), added power to the left engine, and banked the airplane to the right. He then crabbed it and flew back to the runway. He estimated that he landed the airplane about 2/3 of the way down the runway, but touched down prior to the intersection of runway 33. The flight instructor told investigators that he didn't feel the wing touch anything as they landed on the runway. He noticed the wrinkles in the left wing as they taxied off the runway. He estimated that they could have been approximately one wingspan off the runway when they landed. The flight instructor said that he had given the student pilot more than 40 hours dual time in this airplane. The student pilot stated that they preflighted the airplane and took the airplane over to the fuel pumps and filled the tip tanks and added 5-gallons to each auxiliary tank. He said that they circled the Boulder Dam and proceeded toward Lake Mead and then proceeded back toward the Boulder City airport. They entered the pattern using a right downwind pattern for runway 27L. He set the flaps at 15 degrees during the downwind leg, and stated he was high on base. He extended through the centerline of the runway and then corrected back for lineup on final, as he was high. The student pilot said he was shooting for an extended threshold and crossed the threshold at 30-35 feet agl. At 10-15 feet agl, he said the stall warning horn came on and he added power to level off, and then eased the power back and did not pull the throttle back on the right engine, only the left. He said this caused the right wing to rise and the airplane yawed left. He said he tried to correct by pulling the yoke back with large inputs for right rudder and right aileron, but it had no effect. He said he yelled "Gene," and then the flight instructor took the controls of the airplane and flew the airplane back to the centerline of the runway and landed. The Safety Board was not notified of the accident until January 27, 2000.