Volunteers continue their search by air and foot for missing Minnesota pilot.Major Al Pabon (pay'-bon) says the civil air patrol is slightly expanding its search grid beyond the 4,000 square miles already covered.Pabon says 10 airplanes and five ground crews searched an area between St. Cloud and Fosston Tuesday.Family members say pilot Andrew Lindberg of Farmington left the Airlake Airport near Lakeville on Friday in a PA-28 piper Cherokee.He was planning to go to Hallock, in northwestern Minnesota.