On June 15, 2003, a Schleicher ASW-20 (registration N34LB) was involved in an aviation accident near Idyllwild, CA. Investigators recorded the probable cause as: The combined effects of a loss of thermal lift and a gust induced loss of airspeed at a low above ground altitude, which resulted in a descent to impact with trees. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A glider struck trees after losing thermal lift while attempting to climb a mountain in gusty wind conditions, resulting in the wings being sheared off and the fuselage coming to rest inverted.
Incident Overview
A glider impacted trees after experiencing a loss of thermal lift during gusty wind conditions. According to the pilot, there were no control problems with the glider.
Sequence of Events
After release from the tow plane, the pilot made repeated attempts to ascend a mountain. However, insufficient thermals were found to accomplish the climb. On the third attempt, the airspeed suddenly decreased from 55 to 40 knots, and the glider lost 100 to 200 feet of altitude. The pilot lowered the nose to prevent a stall.
Maneuver and Impact
A dead tree was present to the left of the glider. The pilot executed a nose-down, right turn downslope in order to maintain speed and regain terrain clearance. Shortly thereafter, the wings collided with trees and were sheared from the fuselage. The fuselage went through two trees and came to rest inverted.