On June 10, 2016, about 1610 eastern daylight time, a Cessna 310G, N8943Z, collided with a berm while landing at Orlando Apopka Airport (X04), Apopka, Florida. The airline transport pilot was not injured, and the airplane was substantially damaged. The airplane was registered to SOFI, LLC, and was operated by a private individual under the provisions of 14 Code of Federal Regulations as a Part 91 local, post maintenance test flight. Visual meteorological conditions prevailed and no flight plan was filed for the flight that departed from X04 at 1515.The accident flight was the airplane's first flight after an annual inspection. Prior to that flight, it had not been operated in the previous 2 years.

The pilot stated that after release from the inspection, he performed a preflight inspection and noticed several discrepancies, none of which were related to the aircraft's brake system. After the airplane was removed from the hangar, he started the engines and taxied to a place where he fueled the airplane, and during the taxi, he did not indicate any issues with the aircraft's brakes. Following fueling he taxied to runway 33, a 3.987-foot-long asphalt runway where he initiated takeoff and remained in the traffic pattern performing two touch-and-go landings to the same runway.

After the second touch-and-go landing, he remained in the traffic pattern and intended to perform a full-stop landing; however, he had to initiate a go-around because another airplane was on the runway. He returned and reported the touchdown was normal and in the normal/typical location. After touchdown he retracted the flaps and allowed the airplane to slow aerodynamically to the end of the runway. As the airplane approached the end of the runway, the pilot applied the normal brakes; however, the left brake did not function. The airplane started drifting to the right, and as the airplane slowed to a slow taxi speed, the right deviation became more pronounced and he pumped the left brake and applied pressure but it seemed the left brake pedal went to the floor with no pressure or effect. When it became evidence that the airplane would depart the runway he secured the engines, and attempted to maintain control while applying the right brake in an effort to slow the airplane. The airplane went off the right side of the runway at the end and contacted upsloping terrain which caused spar damage to the left horizontal stabilizer.

Operational testing of the pilot's side brakes by a Federal Aviation Administration (FAA) operations inspector following recovery revealed no discrepancies; however, operational testing of the brakes on the copilot's side revealed a discrepancy with the right brake. No brake system leaks were noted and the fluid levels in both brake master cylinders were at the correct level. The airplane was retained for further examination.

Further examination of each brake master cylinder was performed by an FAA airworthiness inspector. Following removal from the airplane, the left brake worked once but on the second actuation, the actuating rod slowly leaked internally to the bottom. The right brake worked perfectly when removed. Both cylinders had an acceptable fluid level after removal. Disassembly of the brake master cylinders revealed all o-rings were in a reasonable condition with no visible cuts or tears. The left brake had a dark crusty compound and a small washer in the reservoir, while the right brake had the same compound including the washer, but was not as contaminated as the left. It was not possible to determine part numbers or serial numbers of either brake master cylinder as the data plates were damaged by hydraulic fluid.

According to the facility that performed the inspection, they utilized a generic twin-engine checklist to perform the inspection. The owner/general manager of the facility where the inspection was performed stated there were no discrepancies related to the brakes during the engine run-ups prior to the inspection.