On October 8, 2011, approximately 1300 eastern daylight time, a Piper PA-28-235 single-engine airplane, N9444W, sustained substantial damage when it impacted the visual approach slope indicator equipment during landing at Weltzien Skypark Airport (15G), Wadsworth, Ohio. The commercial pilot and three passengers were not injured. The airplane was registered to a private individual 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 flight departed Parkersburg, West Virginia, approximately 1215. According to the pilot, he and the passengers departed 15G earlier in the day to attend a breakfast in Parkersburg. The pilot reported that prior to the flight to Parkersburg and the return flight to Wadsworth, no anomalies were noted with the airplane and its brake system. After touchdown at 15G, the pilot applied the brakes to slow the airplane to exit the runway and "nothing happened." The airplane departed the runway surface, and the right wing contacted the visual approach slope indicator (VASI) system. The airplane came to rest upright adjacent to the runway. Postaccident examination of the airplane by the Federal Aviation Administration inspectors and the airplane owner revealed the left brake caliper was leaking fluid, and no fluid was noted in the brake system reservoir. Fluid was then added to the reservoir and a leak was noticed at the brake caliper without any brake pressure being applied to the system. The brake caliper and brake plates were removed. The brake plates showed that they were worn beyond service limits, which resulted in an over extension of the brake piston and failure of the piston seal. The failure of the piston seal resulted in the loss of hydraulic fluid. A review the airframe logbooks showed the most recent annual inspection was completed in March 2011. The brakes were replaced in 2008 and no additional entries in the logbooks were noted that specified the brake system. Since 2008, the airplane had completed approximately 55 landings, and 12 landings since the most recent annual inspection.