What happened
Before departing from Calgary, Canada, for Vancouver, Canada, the pilot notified maintenance staff of the intended flight path. Following takeoff, no radar data was available to track the aircraft during its en route portion.
At approximately 0755 local time, law enforcement received a report from an individual who observed a twin-engine airplane flying at a low altitude near the Snake River. Later, at approximately 0845, a second witness reported seeing a twin-engine airplane on the east side of the Salmon River. This aircraft was estimated to be at an altitude between 200 and 500 feet above the ground, traveling in a north-northwest direction while paralleling the river. The witness noted that the engine performance did not appear irregular before the airplane disappeared from view.
The wreckage of the twin-engine airplane was located at 0930 in a remote forested area. The debris path began with multiple severed trees and extended approximately 555 feet on a southerly heading.
The investigation
Upon inspection of the wreckage, investigators found that both wings had separated from the fuselage and all fuel tanks were breached. While the vertical stabilizer and rudder remained attached to the empennage, the stabilator and elevator had separated from the aircraft. There was no post-impact fire.
An examination of the airframe, engines, and aircraft logbooks revealed no pre-existing anomalies that would have prevented normal operations. However, post-accident toxicology testing of the pilot revealed a carboxyhemoglobin level of 17%, a concentration of carbon monoxide expected to cause measurable impairment of cognitive function.