On September 11, 2000, about 1400 Alaska daylight time, a tundra tire equipped Piper PA-18 airplane, N18PX, sustained substantial damage during landing on a gravel bar, about 60 miles west-southwest of Iliamna, Alaska, at latitude 59 degrees, 45.021 minutes north, and longitude 156 degrees, 52.680 minutes west. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, and the sole passenger, were not injured. Visual meteorological conditions prevailed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on September 16, 2000, the pilot reported he was landing on a gravel bar along the Mulchatna River. Just before touchdown, the pilot said a gust of wind blew the airplane to the left of the intended touch down point, but he said he decided to continue the landing. During the landing flare, the underside of the left wing struck a tree stump that the pilot did not see. The airplane spun to the right and struck the ground. The airplane received damage to the right wing, and the right horizontal stabilizer.