NTSB Identification: SEA07FA231
14 CFR Part 91: General Aviation
Accident occurred Friday, August 10, 2007 in Benton, CA
Probable Cause Approval Date: 01/14/2009
Aircraft: Schempp-Hirth Ventus-CM, registration: N41BM
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.


The pilot departed in a 58-foot-wingspan single-seat motor glider for a round-robin cross-country flight. The intended flight path passed over steep, rugged, mountainous terrain, which had a maximum elevation of 14,100 feet. Four other gliders departed with the accident glider, and the four returned to their departure base about an hour later due to unfavorable winds out of the south and weak lift. The pilot was very experienced with the terrain and proceeded on. His last communication with the four returning gliders was that he was at 16,700 feet and he was headed for a major peak (13,700 feet) on his route of flight. Search and rescue activities were initiated when the pilot failed to return. Friends of the pilot located the missing glider two days later. The wreckage impact signatures, ground scars, and the debris field were consistent with the glider impacting the mountain in a nose-down vertical descent consistent with a spin. The recorded wind at a nearby weather station was from 180 degrees at 16 knots, gusting to 24 knots. The mountain peak and gorge type topographic features within 1.5 miles directly upwind from the accident site could easily have generated mountain wave and turbulent conditions in the area of the accident.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's failure to maintain aircraft control while maneuvering and the inadvertent entry into a stall/spin. Contributing to the accident were the mountainous terrain conditions, unfavorable wind conditions, and the terrain-induced turbulent wind conditions.

Full narrative available

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