Incident Overview
An aircraft disappeared from radar while navigating the Owyhee Mountains. The pilot had received a preflight weather briefing earlier, which noted a recent frontal passage in the area with strong winds and turbulence associated with thundershowers along the initial route of flight until clear of the Owyhee Mountains. No flight plan was filed for the flight.
Preflight and Weather
The preflight weather briefing indicated that a frontal passage had occurred recently, bringing strong winds and turbulence in conjunction with thundershowers. The briefing described these conditions along the initial portion of the planned route, lasting until the aircraft was clear of the Owyhee Mountains. Despite this, the pilot did not file a flight plan.
Radar and Witnesses
Radar data tracked the aircraft's target as it proceeded south into the mountains, where the target ultimately disappeared from radar. Analysis of the radar data showed the target circling before its disappearance. Witnesses at the Boise, Idaho airport reported that the Owyhee Mountains, which are normally visible from the airport, were obscured by clouds at the time of the occurrence. Relatives of the pilot indicated that a business meeting had been scheduled for that morning at the destination.
Investigation Findings
Investigation of the accident site revealed that the aircraft had impacted terrain while in a descending left turn at a high rate of speed. The aircraft's trajectory and impact signature indicated a high-energy collision with the ground.