Amateur-built S6 N644RS accident near Richland, Washington

Probable cause

The pilot's inability to arrest a descent rate or maintain altitude after encountering a downdraft while maneuvering at low altitude near mountainous terrain that resulted in a hard landing.

NTSB analysis

The pilot reported that, while maneuvering at low altitude on the leeward side of a ridge to follow elk, he encountered a downdraft and the airplane slightly pitched up and the airspeed decreased. The pilot lowered the nose attitude, applied full engine power, and turned away from the hill, however the airplane's descent rate continued to increase. Near the ground, the pilot tried to flare in ground effect but the descent rate did not slow as expected and the airplane landed hard, bending the left main landing gear under the airplane and substantially damaging the left wing when it struck the ground.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR20CA218 for the full record.