2008_08_licpc.jpgThe National Transportation Safety Board is investigating the fatal crash of a single-engine plane carrying three people, including a Long Island man headed to Boston for cancer treatment. The flight was arranged by nonprofit Angel Flight, which gives free flights to people needing medical care; pilot Joseph Baker and Riverhead resident Robert and Donna Gregory were killed. It does not appear a distress call was made before the BeechcraftG35 Bonanza plane crashed in Easton, MA supermarket parking lot on Tuesday. The Gregorys' family are preparing to meet with counselors on how to tell their four-year-old twins their parents have died.