Cessna 310Q N8187Q accident near Steamboat, Colorado

Probable cause

The pilot's failure to maintain clearance from mountainous terrain in day visual conditions. Contributing to the accident was the pilot's impairment due to marijuana and inadequate medical oversight of the pilot by the Federal Aviation Administration.

NTSB analysis

The commercial pilot departed on a cross-country flight over mountainous terrain in day, visual meteorological conditions. The pilot had filed a flight plan but it was never activated and an Alert Notification (ALNOT) was issued when the airplane did not reach its destination. The airplane struck trees in a shallow descent into slightly rising terrain at an elevation of 9,800 feet mean sea level, approximately 27 miles east of the departure airport. Examination of the airplane and both engines revealed no mechanical discrepancies. Postaccident toxicology testing was consistent with impairment of the pilot due to his use of marijuana within three hours of the accident. The Federal Aviation Administration was aware of multiple convictions of the pilot for alcohol-related offenses, but did not request any documentation of those convictions or additional evaluation prior to issuing the pilot a second-class medical certificate.

Text from the NTSB. Open the NTSB docket for DFW08FA153 for the full record.