What happened
A flight departing from El Monte, California, at 1703:3/4 collided with hilly desert terrain approximately 8 miles west of its destination airport. Radar tracking showed the eastbound aircraft maintained a Mode C altitude of 8,300 feet mean sea level until its last return at 1832:31. The wreckage of the unidentified aircraft was found highly fragmented and burned, spread across a 130-foot-long debris field about 1/2-mile west of the final radar position.
At approximately 1821, the pilot contacted the Unicom operator to inquire about weather conditions. The pilot reported being in the Los Angeles area, flying at 8,500 feet, and noted that Bullhead City, Arizona, was visible off the left wing. After receiving information regarding the active runway, a distress call was heard over the Unicom radio between 1825 and 1827, with the pilot stating, "Hey Unicom I'm in trouble." Subsequent attempts by the Unicom operator to contact the aircraft were unsuccessful.
The investigation
A meteorological analysis using radar, satellite imagery, and upper air soundings determined that while visual conditions generally persisted along the flight path, merging cloud layers were present near the accident site. These clouds featured bases at 300 feet above ground level and tops reaching 22,000 feet. Additionally, light rain showers likely existed in the immediate area of the impact.
At 1815, the Automated Weather Observation System (AWOS) had reported scattered clouds at 3,000 feet, broken clouds at 4,000 feet, and an overcast layer at 11,000 feet, with winds from 330 degrees at 12 knots gusting to 23 knots. A light rain storm with lightning had passed through the airport traffic area moving southeast to northwest shortly before the accident.