On September 2, 2001, approximately 1700 Pacific daylight time, a Cessna T210L, N6721M, landed with the main landing gear only partially extended at Olympia Airport, Olympia, Washington. The pilot, who was the sole occupant, was not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed Empire, Nevada about four hours prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. There was no report of an ELT activation. According to the pilot, when he moved the gear handle to the down position, the nose gear lowered and locked in place, but both main gear legs failed to fully extend. The pilot then checked the hydraulic reservoir and found it empty. He therefore filled the reservoir with water and tried again to lower the gear, but was unsuccessful. He then attempted to maneuver the aircraft in a manner that would cause the main gear legs to fully extend by gravity, but they did not do so. Since the gear could not be moved up or down, the pilot was forced to land with the nose gear fully extended and both main gear partially retracted. During the landing, both main gear folded back into the wheel wells, allowing the empennage to impact the runway surface. A post-accident inspection revealed that the nose gear extension actuator gear-down hydraulic hose had failed, and the hydraulic fluid had drained from the system through this failure. The failure consisted of the hose fitting (with a portion of the hose outer skin still attached to it) separating from the body of the hose. The hose was able to be positively identified as an original equipment Cessna part (#S2178-3-0144 ). According to Cessna's Special Inspection Items list for this aircraft, this hose should be inspected and replaced as required each 1000 hours or five years. The location of the failure of the hose's outer skin was approximately 3/32 of an inch inside the fitting collar, and would not normally be in view during an on-aircraft visual hose inspection. A review of the aircraft log books revealed that the last time a nose wheel hydraulic actuator hose had been replaced was 25 years prior to the accident.