What happened
The aircraft was operating under night visual flight rules on a cross-country flight when it impacted the ground near the summit of hilly terrain at an elevation of approximately 1,840 feet. The exact time of the collision remains unknown, but records indicate the flight had departed Groveland, California, sometime between 19:00 and 19:30 Pacific Standard Time.
Local witnesses in the vicinity reported that a sudden rain squall moved through the Livermore area at approximately 19:00 PST. This weather event coincided with the presumed time of the accident. At an airport located approximately five miles northwest of the crash site in Livermore, the weather observation at 19:45 PST indicated scattered clouds at 3,000 feet and broken clouds at 7,000 feet. The elevation of this reporting station is 397 feet.
The investigation
A thorough examination of the wreckage was conducted to determine the mechanical status of the aircraft prior to impact. The inspection revealed no evidence of pre-impact mechanical failure or malfunction. The structural damage was consistent with a high-energy collision with the ground.