Cessna 182 N3371U accident near Goodyear, Arizona

Probable cause

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

NTSB 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.

Text from the NTSB. Open the NTSB docket for WPR20FA049 for the full record.