Lear Jet N1021B, operated by Mack Truck, Inc., of Allentown, Pennsylvania, crashed at approximately 1107 c.s.t., November 6, 1969, into Lake Michigan while executing an instrument approach to Runway 22 at the Horlick-Racine Airport, Racine, Wisconsin. The flight had departed from Benton Harbor, Michigan, on an Instrument Flight Rules flight plan en route to Racine, Wisconsin. The flight had originated at Allentown earlier in the day. There were seven people aboard the aircraft; the pilot, copilot, and five passengers, none of whom have been found to date.
Shortly after the accident, a small amount of wreckage was recovered from the surface of the water. The flight was being vectored by radar to the Automatic Direction Finder final approach course to Runway 22 by Milwaukee Approach Control. Radar contact was lost shortly after the flight was advised that it was passing the Marion Intersection, a radar fix 3.6 nautical miles northeast of the radio beacon which is located on the southern boundary of the airport.