Primary finding
Probable cause
The pilot’s exceedance of the glider’s critical angle of attack while maneuvering over rising mountainous terrain, which resulted in an aerodynamic stall.
Investigator assessment
Analysis narrative
The pilot of the glider reported that, while circling over rising mountainous terrain in search of thermals, he approached a "ridge right in front of me [him]." He added that, at that moment, "the [flight] controls went soft [and] I [he] could see that I [he] was [aerodynamically] stalled and plummeting toward the terrain and trees below." He further added that he "pointed the [glider's] nose down at a steep angle" to gain airspeed, but the glider impacted trees and steep terrain. The fuselage and both wings sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the glider that would have precluded normal operation.
Source record
Factual narrative
The pilot of the glider reported that, while circling over rising mountainous terrain in search of thermals, he approached a "ridge right in front of me [him]." He added that, at that moment, "the [flight] controls went soft [and] I [he] could see that I [he] was [aerodynamically] stalled and plummeting toward the terrain and trees below." He further added that, he "pointed the [glider's] nose down at a steep angle" to gain airspeed, but the glider impacted trees and steep terrain. The fuselage and both wings sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the glider that would have precluded normal operation.