On February 14, 1998, about 1330 eastern standard time, a Aviat, Inc. A-1, N49364, impacted the water while attempting to pickup a banner for towing in Clearwater, Florida. The airplane was operated by Aerial Billboard Corporation under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The commercial pilot and passenger were not injured, and the airplane sustained substantial damage. The flight originated from Clearwater, Florida at 1315. According to the pilot, he made a series of "patterns" to prepare for a banner pickup off a pontoon boat. He began the pattern at 400 feet mean sea level (msl) and descended to 100 feet. On his last pattern, the pilot turned onto the base leg at 100 feet, and he stated the airspeed seemed slower than the indicated 65 miles per hour (mph). The pilot stated the left wing then dipped, and the airplane began a descent. The left wingtip struck the water, and the airplane cart-wheeled. According to the FAA, the pilot was making a left turn at an altitude of 100 feet when the left wing stalled. The airplane then rotated left, lost altitude, and struck the water. The FAA inspector also noted the airplane was over maximum gross weight.