On June 20, 1999, at 1045 central daylight time (cdt), a Beech B19, N282L, operated by a private pilot sustained substantial damage while on approach for landing at Haerr Field, Taylor, Missouri, when the airplane was struck by a Robinson R-22 Beta Helicopter, N2341J. Both aircraft subsequently landed without further incident. The helicopter received minor damage. Visual meteorological conditions prevailed at the time of the accident. Both aircraft were conducting separate personal flights under 14 CFR Part 91. Neither aircraft was operating under a flight plan. The pilot of the B19, and the pilot and passenger of the R-22 Beta, reported no injuries. The airplane was on a cross-country flight which originated at Springfield, Illinois, at 0945 cdt. The helicopter was on a cross-country flight which originated from a private field 6 miles north of Quincy, Illinois, at 0910 cdt. In his written statement, the airplane pilot said that he approached Haerr Field from the east. At approximately 7 miles from the field, the pilot said he switched to the field's common frequency, 122.8 Megahertz, and announced that he would enter a left downwind traffic pattern for runway 15. The pilot said that he heard the helicopter ask where he could land. Someone responded over the frequency and told the helicopter to land behind a large hangar. The pilot said he assumed that the helicopter was flying near the west end of the field. He said that he never saw the helicopter. While turning onto base leg, the pilot said that he watched a Cessna airplane begin his takeoff roll. He started his turn from base leg to final when he heard a noise and felt something. The pilot said that he looked to his left and saw a small helicopter flying below him at his 10 O'clock position. The pilot then noticed that his left aileron was damaged. The pilot said that his airplane and the helicopter appeared to both be under control. The pilot continued his approach and landed without further incident. In his written statement to the Federal Aviation Administration (FAA), the helicopter pilot said that he was coming around for an approach pattern. He had heard the pilot of the airplane over the radio and thought that the airplane was already on the ground. After turning onto final for runway 15 and at approximately 300 feet above ground level, the helicopter pilot said that he felt a large bump in the airframe. The helicopter pilot said that he thought he had hit a bird. He rapidly descended toward the ground and landed. The helicopter pilot said that he never saw the airplane. Federal Aviation Administration (FAA) inspectors examined the airplane at Haerr Field, Taylor, Missouri, on June 22, 1999. An arc-shaped tear was observed in the rear upper skin of the airplane's left wing. The airplane's left aileron was severed at mid span. Yellow paint scrapes were observed in the torn wing and aileron skin metal. The left aileron displayed some binding with the torn upper wing skin at the hinge line. Remaining flight control continuity was confirmed. Examination of the engine and other airplane systems revealed no anomalies. Federal Aviation Administration (FAA) inspectors examined the helicopter on June 23, 1999. One of the helicopter's main rotor blades showed chordwise-running scratches on the bottom surface of the blade, approximately 4 inches inboard of the blade tip. Control continuity was confirmed. Examination of the engine and other helicopter systems revealed no anomalies.