Flight Plan and Initial Leg
The pilot departed Coeur d'Alene, Idaho, for Idaho Falls, Idaho, with a planned passenger pickup at Missoula, Montana. An initial weather briefing was obtained before departure.
Misnavigation and Unplanned Fuel Stop
During the second leg of the flight, the pilot misnavigated while avoiding weather conditions. This resulted in an unplanned fuel stop at Lewiston, Idaho, causing a 3-hour delay for the occupants, who had planned to attend a political function. There was no evidence that the pilot obtained an updated weather briefing after the initial briefing.
Weather Encounter and Collision
While en route to Idaho Falls, the aircraft encountered weather conditions that led the pilot to request instrument handling. Shortly after making this request, the aircraft collided with upsloping terrain in a mountainous area. Dark night conditions existed during both the weather encounter and the subsequent collision.
Investigation Findings
The investigation documented the sequence of events but did not state a probable cause for the accident.