On January 2, 2019, about 1130 Pacific standard time, an experimental Progressive Aerodyne Searey amphibious airplane, N24YD, was substantially damaged when it was involved in an accident near Sacramento, California. The private pilot received minor injuries and the passenger succumbed to injuries sustained in the accident 14 days later. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. During a telephone conversation, the pilot reported that he had departed from Napa County Airport (APC), Napa, California, about 1050 with the intent of landing on the American River. After takeoff, he became distracted when he heard another airplane taking off in his direction and he forgot to retract the landing gear. When he arrived at the river, he conducted a normal approach and extended the flaps to 20°. He verbally announced that the landing gear was retracted, but he did not visually confirm it. Just before touchdown, the pilot realized that the landing gear had not been retracted, and the airplane touched down on the water with the gear extended. The airplane nosed down and became partially submerged. The pilot reported that he experienced difficulty egressing the airplane and was not able to egress until after it had partially sank. He then extracted the passenger from the airplane.