A National Transportation Safety Board preliminary report found that after the section of the outer right wing separated, the plane rolled and hit the ground. It came to a stop against a snow bank at the Monmouth Executive Airport on Feb. 15 about five minutes after takeoff.
Three of the five people killed were members of a family visiting from Poland.
The three were family friends of the plane's owner, 45-year-old Jacek Mazurek, of Kearny. He was killed, as was the pilot, 46-year-old Wojciech Nykaza.
The NTSB investigation continues.