What happened
Before departure, the pilot received a weather briefing indicating that instrument flight rules conditions were expected in the vicinity of Oceanside, California. The briefing also noted that moderate turbulence existed below 20,000 feet. After taking off, the pilot obtained an instrument flight rules clearance to climb and cruise at 6,000 feet.
At approximately 20:05 Pacific Standard Time, air traffic control lost both radio and radar contact with the aircraft. Later, the wreckage was discovered in mountainous terrain, located approximately one-fifth of a mile from the location where the last transponder reply had been recorded.
The investigation
An examination of the debris field revealed significant structural separation. Both outer wing panels, the right stabilator, and the vertical stabilizer were found scattered between 130 and 612 feet from the main wreckage site. Additionally, the remainder of the empennage was located 31 feet away, while the bottom section of the fuselage and the rotating beacon were found 823 feet from the primary impact area.
Evidence indicated that the main wreckage had impacted the ground during a near-vertical descent. All separated components showed signs of overload failure. Personnel near the accident site reported seeing shafts of heavy rain. At approximately 20:18, a pilot of a Cessna 210 reported heavy rain about one mile north of the accident site.
Findings
The distribution of the wreckage and the nature of the structural failures suggest a catastrophic in-flight breakup followed by an uncontrolled descent. The presence of heavy rain and moderate turbulence in the area at the time of the incident points to severe weather conditions as a critical factor in the loss of control.