On May 4, 2013, about 1050 eastern daylight time, a Schweizer SGS 2-33A glider, N2045T, registered to and operated by the Civil Air Patrol (CAP), was substantially damaged when it impacted trees and terrain, near Erwinna, Pennsylvania. The commercial pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed. The maintenance test flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. The flight originated from Vansant Airport (9N1), Erwinna, Pennsylvania about 1045. The pilot was critically injured and was unable to provide any information about the accident. According to the tow plane pilot, the glider pilot intended to practice stalls after being towed to an altitude of 3,000 feet mean sea level. After takeoff from runway 07, the tow plane pilot observed the glider yaw to the left, then right, and left again. For most of the flight, the glider appeared to be above the normal tow position with its nose pointed 45 degrees to the right. Approximately 400 feet above ground level, the glider pilot released the tow line and made a left turn. The tow plane pilot observed the glider turn about 180 degrees, where it impacted trees with its right wing, pitched down, and impacted terrain. Postaccident examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed that the rudder controls were rigged backwards. According to FAA records, the pilot held a commercial pilot and flight instructor certificates, with ratings for airplane single-engine land, instrument airplane, and glider. His most recent FAA second class medical certificate was issued on August 30, 2011. As of April 15, 2013, the pilot reported 13,290 total hours of flight experience; of which, 8,960 of those hours were in gliders. The two-seat glider was manufactured in 1977. Review of the glider's logbooks revealed that its most recent annual inspection was completed on May 1, 2013. At the time of inspection, the glider had accumulated 13,626 total hours. According to the mechanic, who performed the annual inspection, the glider was scheduled for a total restoration in the fall of 2012. Due to lack of funding the restoration never took place and the disassembled glider sat on a trailer through the winter. During the spring of 2013, the glider was reassembled and an annual inspection was performed. The rudder had been removed at an earlier date due to previous damage, repaired, and re-installed prior to the annual inspection. The flight was the first flight following the most recent annual inspection. A mechanic performed a flight control check after the annual inspection. According to the mechanic, he stood at the rear of the glider and held the rudder while another pilot sat in the cockpit and moved the pedals. The mechanic could not see which pedal the pilot was pushing and did not verbally confirm the position of the pedals. The 2-33 Sailplane Flight-Erection-Maintenance manual preflight inspection checklist included inspecting the condition, operation, security of attachment and/or other signs of failure of the rudder and other components.