Alexander Schleicher Gmbh & Co ASW 27-18E N129TD accident near Ephrata, Washington

Probable cause

The pilot’s failure to maintain control of the glider during flight and his exceedance of the glider’s design limits during an attempted recovery from a spin.

NTSB analysis

The pilot was preparing for a glider competition with other glider pilots. Witnesses were flying their gliders in the area and reported seeing the glider thermalling, then entering a spin to the right. During the spin, the rotation increased into a rapid rotation and then into a graveyard spiral. One witness reported that during the second spiral rotation the outboard wingtip panels arched upward. Following the flexing of the wings, it appeared that they “...disintegrated...The wings looked like they exploded.” The witness did not see a parachute. Examination of the glider revealed no preimpact mechanical anomalies. Toxicological evaluation of tissue samples from the pilot were consistent with the use of marijuana and of diazepam (a prescription anti-anxiety medication also known by the trade name Valium) at some time prior to the accident, but no blood was available for analysis and no estimate could be made of when the substances were last used or whether the pilot may have been impaired by their use.

Text from the NTSB. Open the NTSB docket for WPR09LA318 for the full record.