N147DDCessna 182T · 2013

The solo student pilot, in the high-performance airplane, reported that prior to takeoff, he observed a "dead still" flag and windsock, indicating "no wind." He added that, during the takeoff roll, a gust of wind pushed the airplane off the runway to the left. He added that he attempted to recover by reducing power, but the airplane impacted a ditch; the nose landing gear collapsed, and the airplane nosed over. He further added that the wind gust occurred after the airplane had "cleared" a large hill to the west of the runway.

The airplane sustained substantial damage to the wings, fuselage, and empennage.

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

A weather reporting station, about 18 miles north of the airport, reported between 1100 and 1320, the wind increased from calm to 8 knots, decreased after 1400, and no gusts were reported. The wind came predominately from the southwest. The airplane departed on runway 16, and the airport is located in an area of low rolling hills.

The Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25B, contains a section titled "Effect of Obstructions on Wind" which stated in part:

Another atmospheric hazard exists that can create problems for pilots. Obstructions on the ground affect the flow of wind and can be an unseen danger. Ground topography and large buildings can break up the flow of the wind and create wind gusts that change rapidly in direction and speed. These obstructions range from man-made structures, like hangars, to large natural obstructions, such as mountains, bluffs, or canyons. It is especially important to be vigilant when flying in or out of airports that have large buildings or natural obstructions located near the runway.

The intensity of the turbulence associated with ground obstructions depends on the size of the obstacle and the primary velocity of the wind. This can affect the takeoff and landing performance of any aircraft and can present a very serious hazard.