HISTORY OF FLIGHTOn June 13, 2020, about 1400 central daylight time, a Vans RV8 airplane, N836JC, was destroyed when it was involved in an accident near Mandan, North Dakota. The private pilot sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. One witness had a meeting with the pilot and others just before the accident flight. The witness walked over to the airplane after the meeting and noticed that the aft cockpit seatbelt was strapped around the control stick. The pilot said that this was done to hold the airplane's flight controls while parked with windy conditions present. This witness reminded the pilot to remove the belt from around the rear seat controls before departure. The witness walked away from the parking area on the ramp and saw the pilot turn around while in the cockpit, but could not see what he was doing. The witness noticed that the airplane's elevator was up as the airplane departed. The airplane became airborne quickly, flew straight up, rolled left, and then went straight down before impacting the ground; a fire ensued. The witness observed that the elevator was in an up position at the accident site and slowly lowered as the fire continued. Another witness stated that it was very "windy," and he noticed that the wind swung the airplane around during its taxi for departure. The pilot continued a 360° turn on the ramp and then taxied the airplane to the runway for departure. The witness noticed that the airplane's elevator was up during this time and it stayed up throughout the takeoff. Upon lifting off the runway, the airplane "immediately" went straight up to about 50 ft above the ground, entered a left bank, then entered a nose-down, vertical descent to impact. The witness along with another witness tried to pull the pilot out, but the airplane was engulfed in flames. AIRCRAFT INFORMATIONThe airplane was a low-wing, tailwheel-equipped airplane with a tandem seating configuration. Both forward and aft seating positions were equipped with seatbelts and flight controls. AIRPORT INFORMATIONThe airplane was a low-wing, tailwheel-equipped airplane with a tandem seating configuration. Both forward and aft seating positions were equipped with seatbelts and flight controls. WRECKAGE AND IMPACT INFORMATIONFederal Aviation Administration inspectors examined and documented the wreckage site. The inboard portions of both wings, the engine, and sections of the fuselage were thermally damaged consistent with a postimpact fire. A ground scar was present south of the wreckage. Linear gouges were observed within the ground scar. The propeller blades exhibited leading edge nicks and chordwise abrasion. The trim tab on the left elevator was displaced downward, consistent with nose-up trim. The cockpit interior was discolored, deformed, and charred. The seatbelt webbing was not identified. ADDITIONAL INFORMATIONThe airplane kit manufacturer had a stated policy in place for all its company pilots that only the pilot’s stick is to be wrapped around the control stick whenever an airplane's controls are secured by wrapping . The copilot/passenger stick is not to be used to secure the controls under any circumstances. MEDICAL AND PATHOLOGICAL INFORMATIONThe North Dakota Department of Health State Forensic Examiner conducted an autopsy on the pilot and took toxicological samples. The cause of death was listed as blunt head and chest injuries with burning by fire. Toxicology testing performed at the FAA Forensic Sciences Laboratory was negative for carboxyhemoglobin, ethanol, and drugs of abuse.