HISTORY OF FLIGHTOn November 10, 2022, about 1140 Alaska standard time, a Piper PA-18 airplane, N7123K, was substantially damaged when it was involved in an accident near Chickaloon, Alaska. The student pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. A friend of the pilot reported that the accident pilot departed in his airplane as a flight of two along the Matanuska River, with another friend in a Cessna 172. He stated that the two airplanes departed Wolf Lake Airport (4AK6), Palmer, Alaska, about 1100. According to the friend, the pilot in the Cessna stated he was flying just above and behind the Piper PA-18. He saw the Piper descend and fly at a low altitude along the river, then strike an unmarked cable that was suspended across the river, about 30 ft above the water. The airplane came to rest inverted in the river. He landed and notified the Alaska State Troopers of the accident. The cable was not new and there was no cable marking system installed. PERSONNEL INFORMATIONThe pilot’s logbooks were not located. AIRCRAFT INFORMATIONThe maintenance logbooks were not recovered. AIRPORT INFORMATIONThe maintenance logbooks were not recovered. WRECKAGE AND IMPACT INFORMATIONThe airplane was recovered from the river for examination. The wings were impact separated; the fuselage was intact and impact damaged. A portion of the cable remained wrapped around the right wing. The engine remained attached to the airframe. The propeller blades remained attached to the engine crankshaft flanges; gouges were present along the leading edge of one of the blades consistent with cable impact. The windscreen v-bar tubing was sheared near the lower attachment point. The left side of the empennage was undamaged. The right side displayed impact damage to the right horizontal stabilizer. The rudder and elevator control cables remained attached and the rudder displayed minor impact damage. ADDITIONAL INFORMATIONAccording to the owner of the property where the airplane came to rest, the cable that the airplane impacted was installed in the late 1940’s. The cable was the only way to reach the land and houses on the other side of the river. The cable was not marked in any way and was suspended about 30 ft above the river. According to an FAA inspector, the cable had been charted in a caution box on the FAA VFR Sectional Chart, but the caution was removed from the chart in 2019. It was readded to the FAA charts in February 2023. MEDICAL AND PATHOLOGICAL INFORMATIONThe Alaska State Medical Examiner’s Office performed the pilot’s autopsy. According to the pilot’s autopsy report, his cause of death was blunt force injuries and his manner of death was accident. The autopsy identified mild to moderate coronary artery disease, with 50% narrowing of the left anterior descending coronary artery and 30% narrowing of the left circumflex coronary artery. The remainder of the autopsy examination, including visual and microscopic examination of the heart, did not identify other significant natural disease. At the request of the Alaska State Medical Examiner’s Office, NMS Labs performed postmortem toxicological testing of heart blood from the pilot; this testing detected delta-9-THC at 5.2 ng/mL. Postmortem toxicological testing by the Federal Aviation Administration (FAA) Forensic Sciences Laboratory identified carboxy-delta-9-THC at 2 ng/mL in blood and at 3.9 ng/mL in urine. Delta-9-THC is the primary psychoactive chemical in cannabis, including marijuana and hashish. Delta-9-THC may be inhaled or ingested recreationally by users seeking mind-altering effects. It may also be used medicinally to treat illness associated nausea and appetite loss. Psychoactive effects of delta-9-THC vary depending on the user, dose, and route of administration, and may impair motor coordination, reaction time, decision making, problem solving, and vigilance. A person’s instantaneous blood concentration of delta-9-THC does not directly predict that person’s impairment. Carboxy-delta-9-THC is a non-psychoactive metabolite of delta-9-THC. Delta-9-THC and its metabolites have modest potential for postmortem redistribution. Delta-9-THC is a federally controlled substance, and the FAA considers it unsuitable for flying, regardless of state cannabis laws.