HISTORY OF FLIGHTOn February 24, 2022, about 1340 Pacific standard time, a Distar CZ AS Sun Dancer motorglider, N588V, was destroyed when it was involved in an accident near Boulder City, Nevada. The pilot was fatally injured. The glider was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. An employee of the fixed base operator (FBO) at Boulder City Municipal Airport (BVU), Boulder City, Nevada, the departure airport, reported that “something was off” with the accident pilot’s demeanor, and, although his speech was clear, “he still seemed a little woozy.” Recorded automatic dependent surveillance-broadcast (ADS-B) and L3Harris' OpsVue data showed that the glider departed from BVU about 13:15 local, on a westerly heading, climbed to 2,850 ft mean sea level (msl) and entered a left turn. The glider continued the left climbing turn to an altitude of 3,100 ft msl, then began descending on an easterly heading until contact was lost about 13:19 local, at an altitude of 2,375 ft msl, about 1 mile northwest of the accident site. A witness located near the accident site reported that, while performing duties as a site foreman at the solar panel farm near the airport, she observed the glider circling above the solar panel farm at low altitude. The glider’s height appeared to vary from about the top of the power lines to slightly higher. The glider’s engine sounded like it was operating normally, and she did not hear any irregularities, such as backfiring or popping. Shortly after returning to work, she observed black smoke south of the solar panel farm. At the time, she was unaware of any accident. Concerned, she had an employee proceed to the fire and notified emergency services. First responders reported that it appeared that the glider impacted three power lines. The power lines were about 60 ft above the ground, running east to west and black with debris entangled within the power lines. The debris field was located to the south of the power lines and the main wreckage was nearly directly below the power lines. An employee of a FBO located at BVU reported that the accident pilot had rented a vehicle through their rental car service. On the expected date of vehicle return, the employee was informed of motor glider accident. Concerned it may have involved the accident pilot, he proceeded to the parking lot to secure the rental vehicle. While securing the vehicle, he detected an odor of alcohol and observed an open beer can. He locked the vehicle and notified airport operations. PERSONNEL INFORMATIONThe pilot held an airplane multi-engine land, airline transport pilot certificate and a commercial certificate with ratings that includedairplane single-engine land and glider. A review of the pilot’s logbook revealed that he had accumulated about 2,418 total hours of flight experience. He completed about 7 hours of transition training with a flight instructor in the accident airplane about 1 week before the accident flight. His most recent Federal Aviation Administration (FAA) medical certificate examination was in 2008, at which time he reported a recent driving under the influence arrest and was denied issuance based on his history of alcohol use and possible substance dependence. WRECKAGE AND IMPACT INFORMATIONThe main wreckage, which comprised the cockpit and forward fuselage, came to rest upright on a heading of about 172° magnetic, at an elevation of 1,869 ft msl underneath the set of three powerlines. System components and flight control surfaces were scattered throughout the debris path (see figure). Figure: View of accident site diagram. Postaccident examination of the recovered airframe and engine did not reveal evidence of any mechanical anomalies that would have precluded normal operation. Flight control continuity was established from the cockpit to all primary flight controls. Numerous separations were noted within the flight control system with signatures consistent with overload separation or due to the recovery process. MEDICAL AND PATHOLOGICAL INFORMATIONThe Clark County Coroner's Office, Las Vegas, Nevada, performed an autopsy of the pilot. The pilot's cause of death was multiple blunt force trauma. Toxicology testing performed for the coroner’s office was positive for ethanol in the pilot’s peripheral blood at 0.270 grams per deciliter (gm/dL) and his vitreous fluid at 0.308 gm/dL. The sedating antihistamine diphenhydramine was detected at 100 nanograms per milliliter (ng/mL) in his peripheral blood. Caffeine, cotinine (a marker of tobacco use), and nicotine were presumptive positives in his peripheral blood. Toxicology testing performed at the FAA Forensic Sciences Laboratory detected ethanol at 0.251 gm/dL in cavity blood. Ethanol was also detected in vitreous fluid at 0.303 gm/dL and urine at 0.328 gm/dL. Methanol was detected in cavity blood and urine. Diphenhydramine was detected in cavity blood at 296 ng/mL and in urine. Ethanol is a social drug commonly consumed by drinking beer, wine, or liquor. Ethanol acts as a central nervous system depressant; it impairs judgment, psychomotor functioning, and vigilance. Effects of ethanol on aviators are generally well understood; it significantly impairs pilot performance, even at very low levels. While the acute effects of ethanol can vary depending on an individual's frequency of use, body weight, and tolerance, in general, at blood ethanol concentrations as low as 0.02 gm/dL there is relaxation and some loss of judgment and at 0.05 gm/dL there is further degradation of judgment, psychomotor functioning, and alertness. At blood ethanol concentrations above 0.10 gm/dL, there is prolonged reaction time, altered perception of the environment, lack of coordination, slowed thinking, and mood and behavioral changes. Above 0.15 gm/dL, individuals may have significant loss of muscle control and major loss of balance. Methanol, sometimes referred to as wood alcohol, occurs naturally at low levels in most alcoholic beverages. Higher concentrations are found in alcoholic beverages made with denatured ethanol or home-distilled products. Diphenhydramine, commonly marketed as Benadryl, is available over-the-counter in many products used to treat colds, allergies, and insomnia. Diphenhydramine carries the warning that use of the medication may impair mental and physical ability to perform potentially hazardous tasks, including driving or operating heavy machinery. The therapeutic range is 50 to 100 ng/mL, and it has a half-life of 3 to 14 hours. Diphenhydramine undergoes postmortem distribution and central levels may be two to three times higher than peripheral levels. The FAA provides guidance on wait times before flying after using this medication; post-dose observation time is 60 hours, and the medication is not for daily use.