On August 25, 2006, about 0730 Alaska daylight time, a wheel-equipped Cessna 206 airplane, N800NL, sustained substantial damage while landing at an off-airport site about 70 miles northwest of Kodiak, Alaska. The airplane was being operated as a visual flight rules (VFR) other work use flight under Title 14, CFR Part 91, when the accident occurred. The airplane was owned and operated by Newhalen Lodge, Inc., Anchorage, Alaska. The commercial pilot and four passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight originated at the operator's remote fishing lodge near Nondalton, Alaska. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on September 1, the pilot reported that while landing on a gravel-covered beach, he heard a loud thump during the landing roll. During the pilot's postflight inspection, he discovered substantial damage to the leading edge of the left horizontal stabilizer and left elevator assembly. The pilot said he was unable to identify the object that struck the airplane's tail, but thought a large rock may have been dislodged by the airplane's main landing gear wheels during the landing roll on the gravel-covered site. The pilot also noted that the beach-landing site is commonly used by sport fishing lodges in the area. The pilot reported that there were no preaccident mechanical anomalies with the airplane.