Cessna 172H accident near Walnut Grove, Missouri, January 4, 2011

The NTSB's narrative final · quoted from the NTSB record

The accident occurred during the fourth leg of a visual flight rules cross-country flight. The pilot departed on the first leg of the trip shortly after sunrise, about 11 hours prior to the accident. The pilot made 3 intermediate stops during the day, where he purchased fuel. The accident flight was approximately 1 hour in duration and was conducted in night visual meteorological conditions. Radar track data depicted the airplane established on a west-southwest course and at a constant altitude. About 15 seconds prior to the accident, the airplane entered a descending left turn, and spiraled down, ultimately impacting an open field. A postaccident examination of the airplane did not reveal any anomalies consistent with a preimpact failure or malfunction. Postmortem toxicology testing was consistent with the prior use of a prescription anti-anxiety medication and marijuana. Due to limited samples, a determination could not be made as to when the substances were last used. Accordingly, no determination was made as to whether the pilot was impaired at the time of the accident. While the departure from controlled flight suggested spatial disorientation, and the extended duration of the trip likely contributed to pilot fatigue, the exact nature of the loss of control could not be determined.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.