According to the pilot, he was performing both water and pavement touch-and-go landings in his amphibious airplane. On final approach for a water landing, he observed a jet ski come out of a slew area and his attention was drawn to it. Upon landing, "I found myself inverted." Federal Aviation Administration inspectors responded to the accident site and examined the wreckage. The landing gear and the cockpit-mounted landing gear switch were found in the down (extended) positions. A cockpit placard was installed, that stated, "DO NOT LAND ON WATER UNLESS GEAR IS FULLY RETRACTED." The pilot reported no pre-impact mechanical malfunctions or failures with the airplane that would have precluded normal operation.