What happened
On May 22, 2021, at approximately 1830 central daylight time, a de Havilland DHC-2 MK.I, registration N218RD, was involved in an accident near Oak Island, Minnesota. The aircraft was being operated under Part 91 regulations for a personal flight.
Prior to departure, the pilot added hydraulic fluid to the reservoir to address a known leak in the amphibious float landing gear system. During the flight, the left rear wheel extended and protruded from the float. The pilot was unaware that the wheel had moved from its retracted position. Upon landing on the water near the pilot's residence, the extended wheel made contact with the water surface. This contact caused the nose and propeller assembly of the aircraft to enter the water immediately. Following the impact, the occupants exited the aircraft, and the plane subsequently flipped over. The accident resulted in one serious injury (vertebrae fractures) and no fatalities.
The investigation
Because the accident occurred in a remote location, the National Transportation Safety Board and the Federal Aviation Administration did not examine the aircraft. The pilot provided photographs of the landing gear system and a video demonstrating a leak in the system. The pilot stated the leak was caused by a failed o-ring in the lower hydraulic fitting on the jack assembly. The pilot also reported that the aircraft's maintenance records were lost in the water during the accident.