On July 22, 2001, at 1620 eastern daylight time, a Champion 7KCAB, N7537F, piloted by a commercial pilot, sustained substantial damage during an in-flight collision with the terrain near Brooklyn, Michigan. Visual meteorological conditions prevailed at the time of the accident. The banner-tow flight was operating under the provisions of 14 CFR Part 91 and was not on an active flight plan. The pilot, the sole occupant, received serious injuries. The flight departed the Shamrock Field Airport, Brooklyn, Michigan, at 1540 for the local flight. According to the support ground crew, the aircraft had been fully fueled prior to the 1540 departure and had flown with a banner for approximately 40 minutes prior to the accident. The ground crew reported that the aircraft had returned to the airport to drop the banner, retrieve a new banner, and continue with the flight over the Michigan International Speedway. According to the ground crew, the banner did not release from the aircraft during the low approach, and the aircraft executed a go-around in order to enter another traffic pattern. The ground crew stated that the aircraft climbed toward the north and noted no anomalies with the aircraft or its operation. The aircraft was observed to descend and attempt a landing into a cornfield north of the airport. The pilot reported that he has no recollection of the accident. An inspector with the Federal Aviation Administration (FAA) performed the post-accident inspection of the airplane and its engine. No anomalies were found with the airframe or its flight controls that could be associated with any pre-impact condition. The banner was found still attached to the aircraft and was not obstructing any flight controls. The engine was successfully test-run while still attached to the airframe. No anomalies were found during the test-run that could be associated with any pre-impact condition.