On September 9, 2016, about 1130 Alaska daylight time, a float-equipped, de Havilland DHC-2 (Beaver) airplane, N91AK, sustained substantial damage during a collision with water, following a loss of control shortly after takeoff from Uganik Lake, about 35 miles west-southwest of Kodiak, Alaska. The airplane was registered to Redemption, Inc., and operated as Flight 43 by Island Air, as a visual flight rules (VFR) scheduled commuter flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135. Of the three occupants onboard, the airline transport pilot and two passengers all sustained serious injuries. Visual meteorological conditions prevailed, and company flight following procedures were in effect. Flight 43 originated in Kodiak about 1100, with a preplanned, intermediate stop at Uganik Lake, before continuing to the flights scheduled stops in Amook Bay and Zachar Bay, Alaska. According to the operator's director of maintenance the purpose for the intermediate stop at Uganik Lake was to drop off a maintenance technician. He added that another company owned a Cessna 185 that had landed at Uganik Lake earlier in the day and damaged a float, and the maintenance technician was called in to inspect the float prior to the airplane returning to Kodiak. He said that after landing, the accident pilot met the crew of the Cessna 185 on the western shore of Uganik Lake, where he dropped off the maintenance technician, and then he departed for Amook Bay. Witnesses reported seeing the accident airplane back-taxi to the east before it eventually turned around to start the takeoff run to the west, and towards an area of rising, tree-covered terrain. The witnesses consistently reported that after the airplane became airborne, it began a left turn to avoid the rising terrain ahead. As the airplane flew closer to the rising terrain, the left turn steepened, and the airplane began a steep nose down descent. The airplane subsequently struck the shallow waters on the western end of Uganik Lake, and it came to rest partially submerged. The airplane sustained substantial damage to the wings and fuselage. The witnesses to the accident reported gusty wind conditions, from the west, estimated to be between 15 to 25 knots. Due to injuries sustained in the accident, the pilot did not recall the accident sequence; however, he did remember back-taxiing the airplane to the east for a westerly departure. He also recalled variable wind conditions, estimated to be 15 knots, with increasing gusts to 25 knots from the west. The pilot stated that to the best of his knowledge there were no preimpact mechanical anomalies with the airplane. One of the two passengers reported that he was seated in the right front seat, and his wife was seated just behind the pilot on the left side of the airplane. He added that water conditions consisted of 8 to 12 inches of chop on the surface of the water as the pilot started his westerly takeoff run. He said that just after takeoff, the airplane climbed slower than what he was accustomed to from previous flights. He added that as the airplane continued to climb, he could see an area of rising terrain ahead of them. As the airplane approached the area of rising terrain, he said that the pilot turned the airplane very steeply to the left, and then the airplane nosed down abruptly and then began a nosed down, uncontrolled descent into the shallow water below. ADDITIONAL INFORMATION At the time of the accident, the pilot was using a Garmin GPSMAP 496 portable global positioning system (GPS) receiver, capable of storing route-of-flight data. The GPS data logs for September 9, 2016 supported the pilots, passengers, and witness accounts of the accident. A flight track map overlay, and tabular data corresponding to the accident flight are available in the public docket for this accident.