On March 18, approximately 0845 central standard time, a Cessna 172N single-engine airplane, N6372D, was substantially damaged following an in-flight collision with an object while landing at a private airstrip near Rio Grande City, Texas. The private pilot and passenger were not injured. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The local flight originated from the private airstrip at 0815. During a telephone interview conducted by a representative of the NTSB, the 1,561-hour pilot reported that while on a visual approach for landing, the airplane encountered a gust of wind, and the airplane started to "sink." Subsequently, the right main landing gear struck the top of a fence post at the approach end of the 2,000-foot long dirt runway. The pilot stated that after the collision, he noticed that the right main landing gear was separated. As the pilot landed the airplane, it veered to the right off the runway and the right wing and right horizontal stabilizer struck the ground. The airplane came to rest upright adjacent to the runway in a right wing low attitude. Examination of the airplane by the pilot revealed the outboard tip of the right wing and right horizontal stabilizer were bent.