On March 30, 2011, about 1830 central daylight time, a Boeing 737-301 airplane sustained substantial damage during departure from Dayton International Airport, Dayton, Ohio. The airplane was operated by Northern Air Cargo, Inc. (NAC), Anchorage, Alaska, as an instrument flight rules (IFR) positioning flight under 14 Code of Federal Regulations (CFR) Part 91. The captain, first officer, and flight mechanic, were not injured. Visual meteorological conditions prevailed, and an IFR flight plan was filed. The airplane was bound for Laredo, Texas. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on April 5, the Vice President (VP) of Operations for NAC said the cargo airplane was departing Dayton on a positioning flight. He said it appeared that during departure, an unsecured pallet jack in the cargo hold of the empty airplane hit the fuselage frame structure, fracturing a structural frame. He said the airplane was subsequently flown to a repair facility in Tucson, Arizona. In a written report to the NTSB received April 8, The VP reported that the first officer completed the preflight inspection of the airplane while the captain did the paperwork. He wrote that although both pilots looked in the cargo hold of the airplane, neither noticed the unsecured pallet jack.