According to a written statement by the pilot, about 10 feet above the ground, the airplane "dropped hard" onto the runway. An eyewitness stated that the wings shook from side to side, the airplane fell about 10 feet, and the sound of runway impact could be heard. According to marks on the runway, the airplane impacted nose first, bounced, and impacted the runway again. The propeller strike marks associated with the first impact indicated a ground speed of about 38 knots. The impact resulted in substantial damage to the engine firewall. The pilot reported no preimpact malfunctions or anomalies prior to the accident.