Amateur-built Pauper II N70727 accident near Stockbridge, Wisconsin

Probable cause

The pilot's spatial disorientation while maneuvering after takeoff and his subsequent failure to maintain clearance from the terrain. Contributing factors were the snow-covered lake and overcast clouds, which resulted in the pilot's spatial disorientation due to the indefinite horizon. An additional factor was the airplane's low altitude at the time of the occurrence.

NTSB analysis

The pilot of the amateur-built airplane reported that he had attended a chili fly-in and was departing at the time of the accident. An area of a frozen lake approximately 1,800 feet long had been plowed for use as a runway during the fly-in. The pilot stated that he had taken off and the airplane was about 25 to 30 feet above the terrain, when he initiated a turn and subsequently impacted the frozen lake surface. The pilot noted that he had difficulty identifying a clear horizon due to snow covered terrain and the overcast cloud conditions. He added that depth perception is very difficult under those circumstances. The pilot stated that the airplane was mechanically sound and he did not experience any problems with it. He recalled weather conditions as approximately 1,500 feet overcast, with 7 miles visibility. Winds were light and variable at the time.

Text from the NTSB. Open the NTSB docket for CHI08CA073 for the full record.