What happened
Before departing, the pilot obtained a weather briefing from a Flight Service Station, which indicated high winds and mountain obscuration along the intended route. To avoid these adverse conditions, the pilot chose a westerly heading and climbed to 12,500 feet, deviating from the usual altitude of 8,500 feet, while flying across mountainous terrain.
Approximately thirty minutes into the flight, the aircraft encountered strong downdrafts and wind shear on the lee side of the mountains. The pilot applied full power and attempted a 180-degree turn but was unable to maintain altitude. The aircraft descended into a cloud layer where it continued to experience severe turbulence. During this period, the airplane stalled and entered a spin. Although the pilot momentarily recovered from the first spin, the aircraft subsequently stalled and entered a second spin.
The aircraft exited the clouds at approximately 500 feet above ground level. The pilot then performed a force landing into rising terrain.
Findings
- Encounter with strong downdrafts and wind shear on the lee side of mountains.
- Loss of altitude during an attempted 180-degree turn.
- Subsequent stall and entry into two separate spins due to severe turbulence.