At about 1645 eastern time, a Cessna U206G on floats crashed while attempting to land on Lake Thonotosassa. The pilot and passenger were killed. The flight originated at Vandenberg Airport, Tampa, Fla., about 10 minutes prior to the accident. A witness who had seen the accident airplane over the lake many times before noticed that this time the landing gear was down. He said that when the airplane made contact with the water, it immediately nose-dived and flipped straight over. The airplane then sank inverted to the level of the pontoons, with the landing gear remaining extended above the pontoons.