On November 1, 1994, about 1946 central standard time, a Cessna 206G airplane, N9924R, sustained substantial damage while taxiing from landing at the uncontrolled Butler Memorial Airport, Butler, Missouri. The commercial and airline transport pilots, and the two passengers aboard, were not injured. The flight operated under 14 CFR Part 91 in visual meteorological conditions. The purpose of the non-revenue flight was to transport a juvenile hospital patient and his mother to a local hospital. The flight was operated by the Ararat Shriners Wings of Mercy flight program, and was flown by two of their volunteer pilots. The commercial certificated pilot-in-command reported he was taxiing the airplane towards the ramp area to park the airplane, when he turned the airplane onto what he thought was a portion of the ramp. The airplane was actually taxiing on a dirt field, short of the ramp area, and subsequently encountered a drainage ditch. The right main landing gear fell into the ditch, damaging the airplane.