On June 23, 2022, about 1925 Pacific daylight time, a Cessna TR182, N738JZ, sustained substantial damage when it was involved in an accident in Santa Barbara, California. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, he attempted to extend the landing gear while on approach to runway 25 at Santa Barbara Municipal Airport (SBA), Santa Barbara, California. The green landing gear light confirming that the landing gear were down and locked did not illuminate, and he did not hear the familiar sound of the landing gear movement. During the approach sequence, the landing gear hydraulic pump circuit breaker opened, and the pilot reset the breaker, which opened a second time. He subsequently attempted to manually extend the landing gear, but the hand pump did not increase pressure within the hydraulic system. The pilot communicated with tower controllers, and they confirmed that the landing gear were not fully down and locked during a low pass over the airport. The tower controller described the nose landing gear as down, and the main landing gear as, hanging and partially deployed. While the pilot attempted to troubleshoot the situation, he observed a low voltage warning light and declared an emergency. The pilot subsequently landed with the gear partially retracted on runway 25. The left horizontal stabilizer and elevator sustained substantial damage. During the postaccident examination of the landing gear hydraulic system, the right main landing gear downlock actuator was found leaking. To test the hydraulic system, the airplane was placed on jack stands and the system was pressurized. Immediately, hydraulic fluid exited between the firewall 90° Army-Navy (AN) fitting and nut on the right main landing gear downlock actuator. The actuator O-ring was replaced in the fitting and adequate torque was applied to the firewall fitting nut. The hydraulic system was pressurized to 1,500 psi and no additional fluid leak could be traced. An operational system check was performed, and the operational logbook entry was completed. The airframe and powerplant mechanic indicated that during examination of the actuator, the O-ring was present, but the O-ring was “showing its age.” There was no reference to previous inspections or maintenance associated with the actuator.