Schempp-Hirth Nimbus-4M N747JN accident near Ephrata, Washington

Probable cause

The pilot's inadequate preflight inspection and his failure to connect the left aileron control rod during assembly.

NTSB analysis

This was the first flight after removal of the glider from storage and its reassembly. The pilot reported that during takeoff initial climb, the glider started to roll to the left despite his control inputs. He decided to abort the takeoff and land straight ahead while attempting to maintain control of the powered glider. Subsequently, the left wing struck the ground, and the glider began to cartwheel. Examination of the airframe revealed that the left and right wings were structurally damaged and the empennage was partially separated. Examination of the flight control system revealed that the left aileron connecting rod was disconnected at the fuselage/wing quick connection point and was undamaged. The pilot stated that during assembly of the glider prior to the flight, the left aileron control tube was inadvertently not attached, and that he did not verify that all flight controls moved free and correct prior to takeoff.

Text from the NTSB. Open the NTSB docket for SEA08CA122 for the full record.