On October 10, 2022, about 1645 mountain standard time, a Cessna T210L, N2425S, sustained substantial damage when it was involved in an accident near Marana, Arizona. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that this was the airplane’s first flight after an engine overhaul and airframe annual inspection. The pilot reported that he planned a maintenance test flight, and after a normal takeoff, he retracted the landing gear. Shortly after, while on the downwind leg of the airport traffic pattern, he noticed that the landing gear position indicator light was not illuminated. The pilot cycled the landing gear control lever, but the position indicator lights remained unchanged and did not illuminate. Using the mirrors affixed to the airframe, the pilot was able to verify that the nose landing gear appeared extended, and the left main gear door was open but appeared abnormal. The pilot subsequently used the emergency hand pump to extend the landing gear but felt no resistance or hydraulic pressure develop when the pump was actuated. The pilot then made a low pass over the runway and ground personnel confirmed that the nose landing gear was extended; however, the left and right main landing gear were not. The pilot remained airborne about 50 minutes to burn off fuel before landing. He performed a stable approach and touched down before the airplane exited the left side of the runway. The airplane sustained substantial damage to the left horizontal stabilizer and elevator. Postaccident examination of the landing gear system revealed that the left main landing gear actuator retaining ring separated from the actuator cylinder, exposing the internal rod and O-rings. It is not possible to inspect the retaining ring inside the actuator due to the position of the seat being recessed into the cylinder. The actuator currently does not have a specified overhaul time or cycle limit.