On July 5, 2014, about 1830 central daylight time, a Cessna C152 airplane, N49785, sustained substantial damage when the right wing's rear spar fractured in-flight. The commercial pilot and private pilot onboard were not injured. The airplane was registered to and operated by the US Aviation Group under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident, and a visual flight rules (VFR) flight plan had been filed. The flight originated from Graham Municipal Airport (RPH), Graham, Texas, and terminated at Denton Municipal Airport (DTO), Denton, Texas. The private pilot who was flying the airplane from the right seat reported that while flying at 3,500 feet mean sea level, 10 to 15 nautical miles west of the destination airport, a loud "boom" was heard. The commercial pilot in the left seat also reported that a "boom" was heard, and he subsequently took the flight controls, but did not feel or see any anomalies with the airplane. He continued to the destination airport and landed without further incident. During a post-flight inspection of the airplane, the pilots discovered a hole in the top of the right wing near the fuel cap. Further inspection revealed a fracture in the right wing's rear spar. According to a Federal Aviation Administration Aviation Safety Inspector who examined the airplane, a "corrosion crack" was located where the right wing's rear spar failed. Photographs provided by the FAA showed a compression fracture of the upper aft portion of the right wing's rear spar, about 1 foot outboard of the wing-root. Surface corrosion is visible at the fracture location in the photograph. The lower portion of the spar remained intact. The fracture was not examined by the National Transportation Safety Board investigator-in-charge.