Accident Description
The pilot reported that upon arrival at the destination airport, he completed the before landing checklist. When he activated the landing gear lever, the nose gear extended normally, but the main landing gear did not extend. The pilot performed the landing gear malfunction procedures without success.
Communicating with ground personnel via UNICOM, the pilot entered left traffic and made a low pass down the runway for visual inspection. Ground personnel observed the nose gear extended and the main gear "dangling." The pilot remained in left closed traffic and attempted to land. During the landing rollout, the airplane departed the left side of the runway.
Investigation
Following the event, the pilot examined the landing gear well and noted hydraulic fluid on the airframe. The registered owner stated the aircraft had received an annual inspection on November 7, 2005, and had not been flown since except for this flight.
The aircraft was recovered to a hangar and placed on jacks. The seats and main gear actuator access plate were removed to locate the source of the hydraulic leak. The hydraulic reservoir was serviced and the system pressurized. Hydraulic fluid was observed exiting the right gear hydraulic down line.
Findings
A screw had penetrated the hydraulic down line, resulting in a complete loss of hydraulic fluid in the down line and consequent failure of the main landing gear to extend.