HISTORY OF FLIGHTOn October 6, 2020, about 0820 central daylight time, a Quicksilver MXL-2 Sport light sport airplane, N2942A, was substantially damaged when it was involved in an accident near Mount Vernon, Indiana. The sport pilot and pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. A witness stated that she saw the accident airplane flying in the area. She watched the airplane come out of a loop then spiral toward the ground. She did not see the airplane impact the ground, but when the airplane was out of view, she heard the sound of an impact. She observed the airplane from her residence, which was 0.33 nautical mile (nm) east of the accident site and about 1 nm northeast of the airport. PERSONNEL INFORMATIONThe pilot, who was the owner of the airplane, was seated in the right seat. The pilot-rated passenger was seated in the left seat. Both occupants were eligible to fly the light sport airplane with a valid driver’s license. An individual who had flown with the pilot about 1 year before the accident recounted that the pilot performed several “dangerous maneuvers” that made him very uncomfortable. He added that the pilot had “good technical skills, but his decision making was very poor.” Another individual had just flown with the pilot in the days before the accident. She reported that the pilot made low passes and dives. She captured numerous photos and videos of these flights from the ground and while flying in the airplane and provided them for the investigation. A review of the videos revealed that the pilot performed several steep climbs and steep descents at low altitude over the runway. Other videos showed the pilot maneuvering the airplane through a small opening in a tree line while on base to final approach for landing. AIRCRAFT INFORMATIONThe airplane was not approved for aerobatic flight per the experimental operating limitations. . AIRPORT INFORMATIONThe airplane was not approved for aerobatic flight per the experimental operating limitations. . WRECKAGE AND IMPACT INFORMATIONThe airplane impacted a harvested crop field oriented on a southwesterly heading and came to rest on its right side. The main wreckage was located about 100 ft from the initial ground impact marks. The engine remained attached to its mount and one propeller blade had separated from the propeller hub. The responding Federal Aviation Administration (FAA) inspector reported that the flight controls were connected and noted no anomalies. The airplane’s metal tubular structure was bent in several places from the impact. The FAA inspector retained a section of fractured tubular structure for examination. There were no other anomalies noted with the airplane or engine. The NTSB Materials Laboratory examined the fractured pieces of structure, which consisted mainly of anodized aluminum tubular supports that were bolted together with a steel alloy bolt. The bolt fracture surface exhibited rupture consistent with overstress fracture. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the sport pilot was performed by the Posey County Coroner's Office, Mt. Vernon, Indiana. The cause of death was multiple blunt force injuries. The FAA's Forensic Sciences Laboratory performed toxicology tests on specimens from the pilot; memantine was detected in the blood and liver. Memantine is used to treat confusion (dementia) related to Alzheimer's disease. An autopsy of the pilot-rated passenger was performed by the Posey County Coroner's Office, Mt. Vernon, Indiana. The cause of death was multiple blunt force injuries. The FAA's Forensic Sciences Laboratory performed toxicology tests on specimens from the passenger; glucose, diphenhydramine, carboxy-delta-9-THC, 11-hydroxy-delta-9-THC were detected in the urine, and diphenhydramine, delta-9-THC, and carboxy-delta-9-THC were detected in the blood.