On October 2, 2008, about 1535 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N788, sustained substantial damage when it nosed over during landing on a remote gravel bar, about 28 miles northwest of Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) local area flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the U.S. Department of Interior, Anchorage, Alaska. The commercial certificated pilot, seated in the rear seat, and the airline transport pilot seated in the front seat, both certificated flight instructors, were not injured. Visual meteorological conditions prevailed, and a VFR flight plan was filed. The flight originated at the Lake Hood Airstrip, Anchorage, Alaska, about 1300. During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on October 6, 2008, an investigator with the Department of Interior reported that the airplane was being operated for pilot proficiency, and to scout landing areas for an off-airport landing clinic. Each of the two pilots aboard planned to fly from the rear seat of the airplane during the clinic, and the rear seat pilot had been designated as the pilot-in-command for the accident flight. The rear seat pilot selected a gravel bar along the Susitna River that was about 2,000 feet long. During the landing roll, he applied excessive braking, and the airplane nosed over. The airplane received structural damage to the right wing lift strut and the left wing.