Champion 7ECA N9624S accident near Sutton, Alaska

Probable cause

The pilot’s failure to maintain airplane control while maneuvering at low altitude, which resulted in an aerodynamic stall/spin and collision with terrain. Contributing to the accident was the pilot’s use of marijuana, which likely degraded his psychomotor ability.

NTSB analysis

The pilot and passenger were reported to be scouting for locations to hunt moose. When the pilot did not return home at his specified time, a search was initiated for the airplane. The wreckage was located in an area of heavy alder brush, about 250 yards upslope of the floor of about a 3-mile-wide mountain valley. The area surrounding the accident site was interlaced with game trails, and numerous moose tracks and signs were in the area. A large herd of moose was also spotted in the same valley in the days after the accident.

The airplane collided with the ground in a nose-low attitude, and impact damage was consistent with a near-vertical descent, indicating that an aerodynamic stall occurred. A postaccident examination revealed no evidence of a mechanical malfunction or failure with the airframe or engine before impact.

Toxicology tests on the pilot were found positive for metabolites of marijuana within the blood and lung tissue. Most behavioral and physiological effects return to baseline levels within 3 to 5 hours after drug use, although some residual effects on specific behaviors, such as complex divided attention tasks, have been demonstrated up to 24 hours after use. Psychomotor impairment can persist after the perceived high has dissipated. Based on the toxicology results, it is likely that the pilot used marijuana on the day of the accident. Although the pilot's use of marijuana likely affected his ability to successfully manage this flight, the exact degree of impairment in cognition, judgment, and motor function could not be determined.

Text from the NTSB. Open the NTSB docket for ANC13FA090 for the full record.