On November 20, 2010, at 2000 eastern standard time, a Cessna 172N, N882AV, registered to MDS Enterprises LLC, experienced an in-flight upset of undetermined origin while maneuvering in the vicinity of Bluffton, South Carolina. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted in accordance with Title 14 Code of Federal Regulations Part 91. The pilot received minor injuries during a forced landing in a river. The flight departed from Hilton Head Airport, Hilton Head, South Carolina, at 1945, en-route to Lowcountry Regional Airport, Walterboro, South Carolina. The pilot stated that while paralleling the river in cruise flight at 2,000 feet mean sea level he felt a "violent" impact/upset and thought something had hit the rudder. The airplane became unstable and started to rock from side to side and he elected to make a forced landing in the river. The insurance company representing the registered owner stated it was not cost effective to attempt to locate or recover the airplane wreckage. The damage to the airplane is assumed to be substantial.