Aviation Accident Summaries

Aviation Accident Summary WPR20FA049

Goodyear, AZ, USA

Aircraft #1

N3371U

Cessna 182

Analysis

The pilot departed his home airport about an hour after sunset for a flight to test the automatic dependent surveillance–broadcast system that had been recently updated on the airplane. Radar data indicated the airplane flew for about 4 minutes on a southwest heading then flew a figure-eight pattern before heading back toward the airport on a northeast heading. The airplane appeared to be on approach to the airport when it impacted umarked and unlit high-tension power lines about 1 mile south of the airport. Postaccident examination of the airplane and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. Toxicology results suggest the pilot had recently used cannabis based on the relative ratios of Delta-9-tetrahydrocannabinol (the main psychoactive component in cannabis) and its metabolites. Specific performance effects of cannabis include decreased ability to concentrate and maintain attention. Impairment in retention time and tracking, subjective sleepiness, distortion of time and distance, vigilance, and loss of coordination in divided attention tasks have been reported. The specific impairing effects from the pilot’s recent use of cannabis likely included impaired judgment and slowed reaction time, which contributed to his unsafe altitude while still 1 mile from the runway, resulting in the impact with the power lines.

Factual Information

On December 21, 2019, at 1822 mountain standard time, a Cessna 182F, N3371U, was substantially damaged when it was involved in an accident near Goodyear, Arizona. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Aviation Regulations Part 91 personal flight. The pilot's wife stated that she had driven him to Glendale Municipal Airport (GEU), Glendale, Arizona earlier that day so that he could pick up his airplane from an avionics shop where he had had an automatic dependent surveillance–broadcast (ADS-B) system installed. When he got to GEU, he had trouble getting the ADSB system to work, and spent the next 2 hours with the avionics shop trying to rectify the issue. After 2 hours, the pilot called his wife to let her know what the situation was and that he was going to fly back to his home airport (Phoenix Goodyear Airport [GYR]). He believed the issue was a software problem, and that he needed to update the software to get the ADS-B to work properly. The pilot’s wife stated that the pilot returned to the house, updated the software, and returned to GYR to conduct a check flight of the ADS-B. At 1801, the pilot texted his wife to let her know that everything looked great and he was going for a short flight. Radar data provided by the Federal Aviation Administration (FAA), identified the airplane's flight track. The radar track showed the airplane depart from GYR and fly on a southwest heading for about 4 minutes. The airplane then flew a figure-eight pattern before heading back toward GYR on a northeast heading. The airplane appeared to be on a straight-in approach for runway 3 when it was lost off radar at 1822. Responding law enforcement reported that the airplane impacted high-tension power lines about 1 mile south of the airport. The power lines were approximately 100 ft above ground level (agl) and were unmarked and unlighted. The airplane came to rest inverted on the ground underneath the power lines. Powerline striations were observed along the entire length of the left-wing leading edge. The left wingtip was separated and observed with burn marks and multiple pieces of wire on the ground. The right horizontal stabilizer was observed with wire striations at the inboard leading edge and skin separation along the leading edge. A postaccident examination of the engine revealed all six cylinders remained attached to their cylinder bays and displayed varying amounts of impact damage. The cylinders were inspected using a lighted borescope; the cylinder bores, piston faces, and valve heads displayed normal operating and combustion signatures. During crankshaft rotation the cylinders displayed good thumb compression and suction. The valves, springs, and rocker arms also displayed normal operating and lubrication signatures. According to official sun and moon data from the US Naval Observatory, sunset occurred at 1726 and the end of civil twilight occurred at 1753 on the day of the accident. An autopsy of the pilot was performed by the Maricopa County, Office of the Medical Examiner, which listed the cause of death as “multiple blunt force injuries.” The autopsy also revealed that the pilot had an enlarged heart (cardiomegaly) and evidence of a previous heart attack and severe coronary artery disease. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory identified metoprolol, clopidogrel, and atorvastatin in cavity blood and urine. In addition, delta-9-tetrahydracannabinol (THC, the main psychoactive component in cannabis) was identified in cavity blood at 11.1 ng/ml along with its psychoactive metabolite 11-hydroxy-delta-9-THC (4.5 ng/ml) and its inactive metabolite carboxy-delta-9-THC (32.1 ng/ml). All three were also found in urine at 15.4 ng/ml, 188.1 ng/ml, and 244 ng/ml respectively. Metoprolol is a prescription medication used to treat high blood pressure and reduce the risk of recurrent heart attacks. It is not generally considered impairing. Clopidogrel, often marketed with the name Plavix, is an antiplatelet drug used to prevent clotting after coronary stenting to prevent recurrent heart attacks. It may increase the risk of bleeding but is not considered directly impairing. Atorvastatin is an anticholesterol drug, often marketed with the name Lipitor, and is not generally considered impairing. THC's mood-altering effects include euphoria and relaxation. In addition, cannabis causes alterations in motor behavior, perception, cognition, memory, learning, endocrine function, food intake, and regulation of body temperature. Specific performance effects include decreased ability to concentrate and maintain attention. The primary metabolite, 11-hydroxy-delta-9-THC, is equally psychoactive, but is rapidly metabolized to the non-psychoactive metabolite carboxy-delta-9-THC. THC concentrations typically peak during the act of smoking, while peak carboxy-delta-9-THC concentrations occur approximately 9-23 minutes after the start of smoking. The pilot’s most recent FAA third-class medical certificate was issued on March 11, 2016. At that time, he reported no chronic medical conditions and no use of medications.

Probable Cause and Findings

The pilot’s failure to maintain clearance from power lines due to his impairment from cannabis.

 

Source: NTSB Aviation Accident Database

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