An investigation continues into the crash that killed a Joplin doctor. The NTSB and the FAA say a preliminary report about the crash could be released in two weeks. 47-year old David Patterson of Joplin died on Friday when his 1973 Cherokee Piper plane crashed just southeast of Crestline Kansas. His friends say Patterson was a very careful pilot and they can`t understand why this tragedy happened. Patterson began flying his private plane three years ago.