On August 9, 1996, a Grumman-schweizer G-164B (registration N6966K) was involved in an aviation accident near Wellfleet, NE. Investigators recorded the probable cause as: failure of the pilot to maintain aircraft control, while maneuvering at low latitude. The hilly (rolling) terrain and unfavorable wind were related factors. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
While spraying over rolling terrain, a pilot experienced violent nose-down and wing-down attitudes, then struck the ground with the right wing, causing extensive damage. No mechanical issues were reported; the pilot suspected windshear.
Accident Sequence
During an aerial spraying operation over rolling terrain, the pilot encountered a sudden and violent nose-down motion of the airplane. This was followed by the aircraft assuming a left wing-down attitude. The pilot was able to recover from the left wing-down condition but then experienced a right wing-down and nose-down situation. Subsequently, the airplane struck the rolling terrain with its right wing, resulting in extensive damage to the aircraft.
Pilot Report
The pilot reported that there were no mechanical deficiencies or operational problems prior to the impact. He stated that he believed the event may have been caused by a windshear condition.
Meteorological Conditions
At the time of the accident, the nearest weather observation station at North Platte, located approximately 21 miles west of the accident site, reported winds from 180 degrees at 10 knots with gusts to 17 knots.