WPR23LA076

The pilot reported a failure of the left brake during the landing roll. The airplane departed the runway surface and impacted a fence, which cause substantial damage to the empennage, right elevator, and horizontal stabilizers. Postaccident examination of the brake system revealed that the left brake master cylinder reservoir was completely empty. It was serviced and tested with no failure or leaks identified. Further examination of the brake system included the removal of the main landing gear pivot trunnion. It revealed that the O-rings, while not visibly damaged, were flat and stiff, which likely allowed the brake fluid to leak out from the main landing gear trunnion to the actuator interface joint when the landing gear was retracted.

On December 26, 2022, at 1645 mountain standard time, a Cessna 210N, N210CU, was substantially damaged when it was involved in an accident at Morgan County Airport (42U), Morgan, Utah. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot of the airplane reported that, after conducting an uneventful flight to Spanish Fork, Utah, he then flew to 42U. He landed normally, and after the nose landing gear touched down, he began to apply the brakes. The pilot stated that the left pedal “had zero pressure” when he applied the brakes, He stated that he pumped the left brake to “pump the brake up,” but that did not work. The pilot stated at that point, there was not enough time to safely reconfigure the airplane for a go-around. He maintained runway centerline with steering and the right brake until the airplane eventually departed the runway surface and impacted a fence. The empennage, right elevator, and horizontal stabilizers sustained substantial damage. The pilot stated that there had been a recurring issue with the left brake and maintenance was performed to correct the malfunction. Since that time, he had flown more than 10 hours with over 25 takeoffs and landings without any issue. The pilot further reported that he did not see hydraulic fluid on the airplane’s undercarriage. Postaccident examination of the brake system revealed that when the left brake was actuated there was no pressure and did not function properly. The right brake operated normally when brake force was applied. The seats and floor panels were removed to facilitate further inspection of the brakes. The left brake master cylinder was removed and disassembled with no evidence of a hydraulic fluid leak of the master cylinder or brake lines in the forward cabin subfloor area. However, the left master cylinder reservoir was completely empty of hydraulic fluid. The O-ring and master cylinder were in a serviceable condition. The brake system was reassembled and serviced with fluid. The left brake was activated with a maximum pressure applied for 5 minutes with no failure or leakages identified. The left landing gear leg and pivot assembly were removed, and the O-rings from the brake fluid transition assembly were undamaged, normally shaped, and flexible to the touch. The main landing gear pivot trunnion was disassembled, and the O-rings did not have visible damage; however, they appeared “flattened and stiff.” There was a significant amount of brake fluid under the aft cabin floor in front of the bulkhead forward of the landing gear door and brake line pivot fitting.