On September 3, 2004, at 1415 eastern daylight time, a Cessna 305A, N5208G, was substantially damaged during a forced landing, after picking up a banner at the Lawrence Municipal Airport (LWM), Lawrence, Massachusetts. The certificated commercial pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local banner-tow flight conducted under 14 CFR Part 91. As the pilot initiated the banner pick up, moderate turbulence was encountered, and the airplane began to descend. The turbulence encounter lasted momentarily, and all of the pilot's visual cues indicated that the banner towline was picked up normally. As the airplane was climbing out, about 300 feet above the ground, the pilot looked over his left shoulder, and observed the banner leave the ground. At that moment, the pilot felt the airplane swerve to the right, and observed that the banner towline was hooked around the right main landing gear assembly. Realizing that the airplane was subjected to increased drag, the pilot lowered the nose, and performed a forced landing to a grass field. As the airplane neared the ground, the banner touched down first, and induced more drag on the airplane. The pilot added additional power to compensate; however, the airplane touched down hard, and continued down an embankment, where it came to rest inverted. The winds reported at the airport, about the time of the accident, were from 270 degrees at 11 knots, gusting to 16 knots.