Incident Overview
A flight en route at 10,000 feet MSL encountered severe downdrafts while flying in scattered cloud conditions. The pilot reported that the air was "relatively smooth with scattered clouds and no obvious warning signs" prior to the event. The downdrafts caused the airplane to enter an uncontrolled altitude deviation and descent.
Speed Exceedance and Recovery
During the uncontrolled descent, the pilot inadvertently exceeded the never-exceed speed (Vne). Airplane control was recovered at 4,400 feet MSL. The pilot did not specify the duration of the upset or the descent rate.
Structural Findings
Post-incident inspection revealed that the horizontal stabilizers were bent downward. No other damage was reported in the available source.
Pilot Report
The pilot noted that the environmental conditions—scattered clouds and relatively smooth air—did not provide any obvious warning of the severe downdrafts that were encountered.