The airplane was destroyed at about 1945 Eastern time when it impacted water while maneuvering. The private pilot was fatally injured. Night visual conditions prevailed. A witness stated the pilot told her he was working on night recurrence training. Two witnesses reported hearing the engine noise increase and observing the airplane in a “nose-dive” toward the ground. The airplane crashed into about five feet of water, on a tidal mud-flat. The accident site was about five miles from the end of Runway 17 at the Marco Island Airport (MKY), Marco Island, Florida, and left of the extended runway centerline.