On December 17, 2003, about 1400 mountain standard time, a Piper PA-11, N5516H, came to rest inverted after attempting to land in a soft dirt field in Gilbert, Arizona. The pilot/owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed, and a flight plan had not been filed. The local area flight departed from Millar Airport, Maricopa, Arizona, at 1330 with a planned destination of the private field. The Federal Aviation Administration (FAA) inspector responded to the accident scene. He reported that the pilot was attempting to land in a soft dirt field. Upon touchdown, the airplane's main landing gear sunk into the soft terrain. The airplane nosed over and came to rest inverted. The damage incurred from the accident included a bent wing strut, a bent rudder, and several holes wing skin. In a written statement, the pilot reported that he was attempting to land in an alfalfa field next to his home. He had successfully completed landings in the field prior to the accident. The dirt in the field had recently been lightly disked. The pilot reported no preimpact mechanical malfunctions or failures with the airplane.