On March 15, 1993, at 1138 eastern standard time (EST), a Piper PA-28R-200, N15206, registered to Suburban Aviation, Inc. of Ottawa Lake, Michigan, disappeared while flying over Lake Michigan. The airplane is missing, and the solo commercial pilot is presumed dead. The pilot of the airplane departed toward Jackson, Michigan, with the intent of taking a flight instructor checkride. The airplane was last visible on radar, during a descent, approximately 11 miles southwest of Grand Haven, Michigan. Visual meteorological conditions prevailed at the time the airplane was believed to have been last observed on radar. The 14 CFR Part 91 flight originated from Lambertville, Michigan, at 1010 EST. The Federal Aviation Administration's (FAA) Cleveland, Ohio, Air Route Traffic Control Center (ARTCC) having responsibility for the area between N15206's departure point and its last presumed contact stated a radar target was observed departing the Toledo Suburban Airport, Lambertville, Michigan, on March 15, 1993, at 1006 EST. He stated the aircraft had a non-discreet transponder code and was not positively identified as N15206 since there was no communication between the aircraft and ARTCC. The FAA representative stated the flight path and altitude of the aircraft was erratic. The flight path involved turns with descending and ascending spirals of various altitudes. The ARTCC representative stated the aircraft's last radar contact was Latitude 42 degrees, 52 minutes, 12 seconds North and Longitude of 86 degrees, 20 minutes, 12 seconds West. The representative stated the aircraft was approximately three to five miles west of Lake Michigan's eastern shore, and four miles south of the Coopersville, Michigan, radar site tracking south-southwest at an altitude of 6,700 feet when radar contact was lost. The Civil Air Patrol (CAP) conducted an investigation which included an air search of the area where ARTCC's last radar target identification was made. The results of the search were negative. The entire area where N15206 was presumed to have flown was over flown by CAP airplanes. The results of the over land search were also negative.