Incident Overview
The pilot of an airplane did not receive a preflight weather briefing from the FAA or NWS systems, according to records. The pilot informed the operator that he changed his destination due to high winds, choosing an area with better weather. Subsequently, the pilot changed his destination a second time without telling the operator, selecting an airport that required crossing the Sierra Nevada mountains.
Weather Conditions
High winds were forecast for the mountain region. While the pilot was on the frequency, approach control broadcast a Center Weather Watch forecasting moderate and occasional severe turbulence, strong up-and-down drafts, low-level wind shear, and wind gusts up to 45 knots. The closest weather observation station, located upwind of the accident site, had taken six special weather observations in addition to two scheduled observations due to changing weather conditions.
Observed Events
Numerous witnesses observed the airplane descending uncontrolled without its tail. After the accident, ice was observed on the wings, in an induction hose, and on the ram air port of the pitot static system.
Probable Cause
No probable cause was stated in the source.