On March 13, 1998, at 1315 central standard time, an Aero Commander 680FLP, N777MX, registered to AFK Corporation, of Ripon, Wisconsin, sustained substantial damage during an emergency landing one-quarter mile south of the Fond Du Lac County Airport, near Fond Du Lac, Wisconsin. The airplane initiated a takeoff from runway 18 (5,940' x 100' dry snow/asphalt), in instrument meteorological conditions with the intended destination of Washington, DC. The instrument rated commercial pilot said the airplane encountered turbulence and did not accelerate as expected. He elected to make the precautionary landing in a corn field. The pilot and two passengers reported no injuries. One passenger received minor injuries. The corporate CFR 14 Part 91 flight was operating on an IFR flight plan. The flight was originating at the time of the accident. The pilot stated in his written statement, "Experienced very rough and turbulent air during the climb to approximately 200 feet AGL, airspeed was very erratic jumping around from 115 to 100 miles per hour, then experienced extreme side shear from the right." He indicated that with full power, continued flight was not possible. He extended the landing gear and executed a landing in a cornfield one-quarter mile off the departure end of runway 18. A weather observation at the airport taken 23 minutes after the accident indicated a wind of 190 degrees at 14 knots with gusts to 21 knots.