Piper PA-28-235 N56626 accident near Livermore, California

Probable cause

The pilot's continued visual flight into instrument meteorological conditions, which resulted in a collision with obstacles and terrain.

NTSB analysis

The flight departed in visual flight rules flight conditions and the non-instrument-rated pilot was returning to her home airport. There was no evidence the pilot obtained a weather briefing prior to departure. An analysis conducted by an NTSB meteorology specialist determined that precipitation passed through the area of the accident site near the time of the accident. A witness that heard the airplane and its subsequent collision with terrain indicated that there was low fog at the time of the accident. Radar data showed that the airplane flew in a straight-line pattern from the northeast to the southwest between its departure and destination and then turned to the southwest when approaching an area of higher terrain. Based on witness information, it is likely that the weather conditions were poor in this area and the pilot was attempting to maneuver the airplane to improved weather conditions at lower elevations on the other side of the higher terrain. Postaccident inspection of the airplane did not disclose evidence of any preimpact anomaly of the engine or airplane systems. The pilot was on a prescription antidepressant medication that would not have been expected to impair her performance. Additionally she also had ingested quinine, which may in some cases contribute to spatial disorientation, although its effect in this accident, if any, could not be determined.

Text from the NTSB. Open the NTSB docket for WPR10FA234 for the full record.