On March 7, 2015, about 1130 Pacific standard time, a Piper PA-18-150, N5385Y, encountered a flight control stick malfunction and impacted rising terrain during a low altitude flight near Merced, California. The pilot (sole occupant) was not injured, and the airplane sustained substantial damage to both wings. The airplane was registered to and operated by the pilot under the provisions of title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, and no flight plan was filed. The flight originated from Pine Mountain Lake Airport (E45), in Groveland, California at 1100. According to the pilot, he applied back pressure to the flight control stick to climb the airplane over an approaching hill, but the control stick separated at the stub. The pilot attempted to reinsert the control stick onto the stub while simultaneously adding power to climb, but the airplane impacted terrain, slid, and came to rest along the hillside. According to the manufacturer's service manual, the flight control stick was constructed from tubular steel that extended to the floor of the airplane where it slides over a stub. A through bolt is then used to secure the control stick to the stub. Photographs of the control stick revealed the through bolt was still secured to the control stick and not to the stub. There was no damage or deformation to the control stick or through bolt. Photographs of the stub also revealed no deformation or damage; the hole designated for the through bolt also sustained no damage and was not elongated. The airplane's most recent maintenance was an annual inspection that occurred on December 19, 2014. Since the inspection, the airplane has flown about 33 hours.