Preflight Briefing
The pilot received a preflight weather briefing indicating mid-level clouds, turbulence, and good visibility. The briefing noted flight precautions for coastal mountain obscurement due to low clouds. Rain showers and low ceilings were forecasted for approximately eight hours after the flight's estimated time of arrival.
Accident Location
The accident site sits at the southwestern end of a small valley, where the terrain narrows into a constricted pass surrounded by high coastal hills.
Witness Accounts
Multiple witnesses reported that the valley was experiencing heavy rain, low clouds, and fog with visibility reduced to half a mile. The aircraft was observed flying down the valley at an altitude of about 500 feet above ground level, following a highway.
Collision Sequence
As the aircraft approached an oil refinery at the southwestern end of the valley, it was seen to execute a sudden right turn just before reaching the refinery's flame stack. The aircraft subsequently collided with the top of a mountain ridge.
Investigation
No probable cause has been determined from the available information. The investigation continues.