On August 21, 2005, about 1300 Alaska daylight time, a Cessna U206E airplane, N9138M, sustained substantial damage during an in-flight collision with terrain on final approach to a dirt airstrip, about 10 miles north-northwest of Skwentna, Alaska. The airplane was being operated by Alaska Air Taxi LLC, Anchorage, Alaska, as a visual flight rules (VFR) on-demand passenger flight under Title 14, CFR Part 135 when the accident occurred. The commercial certificated pilot and one passenger received minor injuries; the three other passengers were not injured. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight departed Lake Hood Strip, Anchorage, about 1210. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on August 21, the director of operations for the operator said that the pilot reported that the airplane touched down several hundred feet short of the landing area. He said the area where the airplane touched down had been cleared of trees, but the stumps were still there. He said the pilot told him the airplane hit a stump and nosed over, coming to rest inverted. He said the wings, fuselage, and empennage of the airplane were structurally damaged. During a telephone conversation with the NTSB IIC on August 22, the pilot said he was on short final when the airplane started to sink rapidly. He said he added power, but the airplane touched down short of the runway, and collided with a stump. He said there were no known mechanical anomalies with the airplane prior to the accident. In a written statement to the NTSB dated August 31, the pilot wrote that when he applied the throttle to arrest the descent, he felt that the throttle did not respond appropriately. He said after the passengers deplaned, he returned to the airplane to check the throttle, but it appeared to function normally.