The flight instructor reported to the Federal Aviation Administration (FAA) inspector that he was planning to demonstrate to the student how to land on the numbers for the runway and set up his approach accordingly. He believed that while crossing the road adjacent to the airport, the sun visor slipped down and after seeing a fence, pulled aft on the control yoke but was too late. The student pilot stated that he saw the flight was, “coming down really fast” and he was about to say something to the flight instructor and pull the control yoke but the airplane impacted the fence with the landing gear. The pilot reported that there were no pre-accident mechanical malfunctions or anomalies that would have precluded normal operation. A post-accident examination revealed substantial damage to the engine mount and wrinkles to the lower and upper skins of the left wing.