Accident Description
The pilot conducted a wheel-up landing after both normal and emergency landing gear extension procedures were unsuccessful in lowering the airplane's landing gear. The aircraft sustained damage to the propeller, lower fuselage skins, and fuselage bulkheads during the event.
Postaccident Examination
Following the incident, retraction tests showed that the landing gear extended and retracted abnormally. Inspection of the landing gear system revealed a deformed spring on the up lock sequencing actuator. After the spring was replaced, subsequent retraction tests operated normally. No other preexisting anomalies were found in the system.
Hydraulic System Review
A review of the aircraft's hydraulic system indicated that a failure of the up lock sequencing actuator had the potential to direct hydraulic pressure to both sides of the main landing gear actuators. This condition could prevent the landing gear from fully extending, consistent with the behavior observed during the incident.