Background
Two Beech 200 aircraft were involved in a positioning flight from Santa Monica, California, to Farmington, New Mexico. Before departure, the pilots evaluated weather reports at a fixed base operation and made a computer weather inquiry. They did not file a flight plan.
Sequence of Events
During the flight, the lead aircraft was about 1 to 3 minutes ahead of the second aircraft. The second pilot reported that they were at approximately 4,500 feet above mean sea level as they approached mountainous terrain. The clouds were observed to be about 1,000 feet above their altitude. Continuing eastward through a valley, the second pilot heard the lead pilot say he was "going up." This transmission was the last communication from the lead aircraft. The second pilot proceeded with the flight, remaining in visual meteorological conditions.
Two days later, the wreckage of the lead aircraft was discovered. It had impacted about 100 feet below the top of a mountain ridge with an elevation of 7,400 feet. The aircraft's heading at impact was approximately 030°. The ridge itself was oriented along headings of 060° and 240°.
Probable Cause
The official investigation determined the probable cause to be improper in-flight planning/decision by the pilot, which resulted in his inadvertent flight into instrument meteorological conditions (IMC) and subsequent collision with mountainous terrain. Weather and terrain conditions were considered related factors.