CHI98LA083

The pilot said he was observing the airplane's shadow as he made a low pass over a snow covered frozen lake at 50 feet. He said he went under a cloud, lost his shadow, and encountered whiteout conditions. The pilot said he could not tell where the lake's surface was because he could no longer see his shadow. He pulled up to gain altitude, but the main landing gear contacted the ice, shearing them off. The wing struts overloaded and broke off on the subsequent bounce. Several publications on winter flying describe whiteout conditions. One book describes the pilots encounter as 'overcast whiteout.'

On January 20, 1998, at 1107 central standard time (cst), a Nerstrom Tailwind W-8, N12038, piloted by a private pilot, was destroyed during a collision with the frozen, snow covered surface of Lake Wisconsin during a low pass. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot reported no injuries. The flight departed Baraboo, Wisconsin, at 1030 cst.

The pilot stated in his written statement that he left Baraboo, Wisconsin, for a short local flight. He said that after 30 minutes of flying he descended over Lake Wisconsin, near Lodi, Wisconsin, to check and see "...if anyone had been using the lake at [the] restaurant area..." for landing. He said that he "dropped down to abut 50 feet over the lake [while] looking out the left door window..." at his shadow. When the airplane went under a cloud, the pilot said he realized he could no longer see his shadow. The pilot said he contacted the ice "... the instant [he] could no longer see [his] shadows."

During a telephone conversation, the pilot said he lost visual reference when the airplane's shadow disappeared. The pilot said that he could not tell where the lake surface was due to the whiteout conditions he encountered. He stated he pulled up to gain altitude, but the main landing gear contacted the ice, shearing it off. He said on the subsequent bounce, the wing struts were overloaded and the wings broke off.

In the book Flight Training Manual by Transport Canada, overcast whiteout is described as "...a uniform layer of cloud over a snow-covered surface." The sunlight is "...scattered and diffused..." in between the overcast clouds and snow surface in all directions. This results in "...the space between the ground and cloud appear[ing] to be filled with a diffused light with a uniform white glow. Depth perception is completely lacking as the sky blends imperceptibly with the ground at the horizon line, causing disorientation."