According to the pilot, during a previous flight on the same day he discovered that the elevator trim adjustment wheel was binding when set to the full airplane nose up position. He planned to have the airplane inspected by a mechanic at the conclusion of that flight, but upon arriving at the destination, all of the facilities were closed for the evening. He subsequently departed for the return flight after picking up passengers, and as he began to trim the airplane for the landing flare, the airplane pitched up uncontrollably. As the pilot attempted to recover the airplane, the left wing struck the ground, resulting in substantial damage. An examination of the wreckage by an FAA inspector revealed that the trim wheel was binding on the instrument panel when the trim was set to a nose up position. When the trim wheel was removed from the trim system, the remainder of the mechanism was free to move in both the up and down directions. The airplane owner also stated that during a flight 3 weeks prior to the accident, the pilot reported difficulty operating the elevator trim.