The airplane departed from the turf airstrip, and according to data recovered from a handheld GPS, it proceeded about 1.5 miles south and then returned to overfly the airport before returning to land. The non-certificated pilot again departed from the turf airstrip. He appeared to return for a touch-and-go landing and then proceeded north about 0.80 mile before returning to the airport. The final GPS data point was positioned about 265 ft north of the accident site and about 34 ft above ground level. A witness observed the airplane taxi out for takeoff with the airplane owner seated in the right (co-pilot) seat and a friend of the owner in the left (pilot) seat. Neither the owner nor the left-seat occupant held a pilot certificate. They took off toward the south. It appeared that the wing flaps were extended, and the engine sounded “fine.” After lifting off, the airplane porpoised, entered a “steep” left turn, and flew out to the north. After returning to the airport, they appeared to be lined up on final approach for the turf runway. As the witness proceeded to open a hangar door, he heard the impact and turned to see the airplane. He responded to the accident site and notified local authorities.The airplane came to rest inverted along the west edge of the paved ramp area. An initial impact ground scar was located about 15 ft north of the main wreckage. The fuselage nose and engine were crushed aft and upward consistent with a nose-low impact. Postaccident airframe and engine examinations did not reveal any anomalies associated with a preimpact failure or malfunction..The airplane owner’s toxicology was positive for ethanol. The consistency of ethanol levels indicates that the owner likely had consumed ethanol, and likely had a very high blood ethanol concentration at the time of the accident. Based on the high blood ethanol concentration, he likely experienced degradation of judgment and significant deficits in coordination, Page 2 of 11 CEN23FA050psychomotor skills, perception, and attention. In addition, toxicology results detected other central nervous system depressant medications including phenobarbital, cetirizine, hydroxyzine, and doxepin, all of which can adversely interact with one another and with ethanol to worsen impairment. The owner’s past flight experience and competency of piloting are unknown. However, the combination of his pre-existing cognitive conditions, identified during neuropsychological testing in 2015 that revealed evidence of a risk of compromised safety, and the impairing effects of his use of multiple substances, likely contributed to poor decision making. In addition, the combination of cognitive conditions and use of multiple substances would have diminished any baseline flying ability he may have possessed. Thus, effects of the owner’s use of ethanol and other depressants, in combination with his baseline cognitive impairment, likely contributed to the accident.The left-seat occupant’s toxicology was also positive for ethanol in all tested specimens at significant levels, including in vitreous fluid. This indicated that he likely had consumed ethanol and had an impairing blood ethanol concentration at the time of the accident. He, too, would have likely experienced degradation of judgment, and deficits in coordination, psychomotor skills, perception, and attention. In addition, the left-seat occupant’s toxicology testing detected the central nervous system depressing medication alprazolam and the antidepressant citalopram. It is likely that the combination of substances worsened his impairment. However, it is unknown if the left-seat occupant possessed any baseline skill or experience relevant to operating the airplane. Thus, whether effects of his impairment contributed to the accident cannot be determined.Both occupants sustained injuries to their hands, wrists, and arms consistent with holding the aircraft controls; the investigation was not able to determine which occupant was operating the airplane at the time of the accident.