Incident Overview
A glider experienced in-flight structural damage while maneuvering at an altitude of approximately 17,500 ft MSL near California City, California. The incident occurred under conditions that included strong surface winds and reported lenticular clouds topping the mountains.
Pilot Statements
In a preliminary verbal statement to an FAA inspector, the pilot said he had performed a couple of loops. After recovering to level flight, he heard several loud bangs and felt severe vibration in the controls. Later, however, the pilot insisted that no aerobatic maneuvers were performed. Instead, he stated that he had encountered turbulence and had flown through a rotor.
Aircraft Damage
Post-incident inspection revealed wrinkles in the skin on the aft fuselage and empennage. The vertical stabilizer was deformed, and the left horizontal stabilizer and elevator showed several areas of deformation.
Weather Conditions
Surface winds in the area were reported from 270 degrees at 22 knots, gusting to 28 knots. Peak surface winds were from 290 degrees at 42 knots. Standing lenticular clouds were observed topping the mountains. SIGMET Juliet 4 was in effect, cautioning occasional severe turbulence below 16,000 ft MSL.