On May 22, 2021, about 1830 central daylight time, a de Havilland DHC-2, N218RD, sustained minor damage when it was involved in an accident near Oak Island, Minnesota. The pilot and one passenger were not injured, and one passenger sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to local authorities who spoke with the pilot/owner after the accident, before the flight, the pilot added hydraulic fluid to the reservoir due to a known leak in the amphibious float landing gear system. At some point during the flight, the left rear wheel extended and protruded from the float. The pilot was unaware of the wheel position and landed on the water near his residence. During the water landing, the extended wheel contacted the water, and the airplane’s nose and propeller assembly immediately went into the water. The pilot and passengers exited the airplane, and the airplane subsequently flipped over. During the accident sequence, one passenger sustained vertebrae fractures. Due to the remote accident location, the airplane was not examined by the National Transportation Safety Board or the Federal Aviation Administration. The pilot provided photos of the landing gear system problem area and a short video demonstrating the leak in the system. According to the pilot, the leak was the result of a failed o-ring in the lower hydraulic fitting on the jack assembly. The pilot reported the airplane’s maintenance records were lost in the water following the accident. The most recent maintenance could not be determined.