On February 27, 2022, about 0958 eastern standard time, an experimental amateur-built Vans RV-12IS, N123RR, was destroyed when it was involved in an accident about 20 miles northwest of Big Pine Key, Florida. The sport pilot and passenger have not been located. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane was reported overdue to the Federal Aviation Administration (FAA) on February 28, 2022, after the sport pilot did not report to work. The vertical stabilizer and right horizontal stabilizer were located by the US Coast Guard on March 4, 2022. As of the publication of this report, no other sections of the airplane have been located. According to a friend of the sport pilot, who kept his airplane in an adjacent hangar, they planned to complete a flight of two to Key West, Florida (EYW). Prior to departure, the friend discussed using Everglades City, Florida (X01) in case they had to divert due to weather. Although they were cruising at 6,500 ft msl, the friend had to descend to 1,500 ft msl to remain below a broken cloud layer. He advised the sport pilot that he was diverting to Marathon, Florida (MTH) and encouraged him several times via radio to do the same; however, the sport pilot stated that he was descending from 6,500 ft msl to 4,500 ft msl and continuing to EYW. That was the last communication the friend received from the sport pilot. The friend added that the sport pilot usually checked weather via a ForeFlight app on his phone; however, review of flight service and ForeFlight records did not reveal any weather briefing for the accident flight. The sport pilot was not in radio contact with air traffic control at the time of the accident. Automatic Dependent Surveillance-Broadcast (ADS-B) data revealed that the airplane was in the vicinity of moderate precipitation, which was forecast, at the end of the data (for more information, see Meteorologist Specialist’s Factual Report in the public docket for this investigation). During the last mile of track data, the airplane entered a descending right spiral. The pilot and aircraft maintenance logbooks were not recovered. According to FAA records, the sport pilot received his pilot certificate on January 20, 2022. At that time, he reported a total flight experience of 88 hours; of which, 24 hours were as pilot-in-command and 0 hours were instrument experience.