The pilot reported that during takeoff from a mountain airstrip, and climbing just above the trees lining the runway, the airplane encountered an "extreme wind shear and an enormous downdraft". The pilot further reported the airplane began to descend at 1500-2000 feet per minute and he decided to land on the remaining runway. Subsequently the airplane touched down hard, bounced, and nosed over. The airplane sustained substantial damage to both wings, fuselage, and empennage.
The pilot reported that there were no pre impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.