On September 1, 1996 at 1621 eastern daylight time, a Karr Titan Tornado, N238PW, was destroyed during impact with the surface of Lake Michigan (terrain) following a intentional low level aerobatic maneuver. The surviving passenger stated that the pilot was performing the fifth consecutive "hammerhead turn" when the accident occurred. The pilot sustained fatal injuries and the passenger minor injuries. The personal 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The flight departed Valpariso, Indiana, about 1521, on a local flight. Witnesses at the scene confirmed the passenger's description of the accident, indicating that they observed the airplane doing low level aerobatic maneuvers at the time of the accident. The Federal Aviation Administration inspector determined that the pilot was holder of a student pilot's certificate and a third class medical certificate dated March 30, 1995. On the application for that medical the pilot stated that he had a total pilot time of 36 hours. A post accident examination of the airplane failed to reveal any mechanical anomalies. The passenger reported no mechanical problems. The post mortem examination of the deceased pilot indicated he was afflicted with "Acute Viral Hepatitis B." There is no indication from the medical examiner's report that the disease had the potential of incapacitation for the pilot. The cause of death was indicated as from drowning. The aircraft wreckage was released to representatives of the owner on September 5, 1996.