What happened
During a flight through the Warner Mountains, an Aero Commander struck mountainous terrain while in the cruise phase. Prior to the accident, the pilot contacted the Reno Automated Flight Service Station to file an IFR flight plan and requested winds aloft information. While the pilot received this specific forecast, no further weather briefings were requested or obtained from official FAA or National Weather Service sources. At the time of the flight, several AIRMET advisories were active, warning of moderate turbulence, icing, and mountain wave activity in the region.
The pilot initially departed under VFR, later obtaining IFR clearance and climbing to 1asc 14,000 feet. After requesting to descend to 12,500 feet, the pilot was informed by air traffic control that the minimum altitude for that segment was 14,000 feet. Consequently, the pilot cancelled the IFR flight plan. During the flight, radar contact was lost near Eagle Peak. The wreckage was located near the crest of the peak on November 23.
Findings
Investigation of the wreckage revealed no mechanical failures in the engines, propellers, or airframe that would have prevented the aircraft from operating normally. However, weather analysis indicated a high probability of severe turbulence between 9,500 and 11,000 feet at the accident site. Other aircraft in the area reported significant mountain wave activity, including updrafts of 2,000 feet per minute and severe downdrafts.
One following aircraft, a turbocharged Aero Commander, experienced a severe downdraft at the same location that caused a continuous loss of altitude despite the use of maximum climb power. The mountain wave activity triggered by the steep terrain of Eagle Peak created intense vertical air movements. The aircraft's flight path entered the lee side of the mountain, where it encountered alternating updrafts and downdrafts that increased in intensity, ultimately leading to the impact.