Incident Details
During an approach, the pilot attempted to extend the landing gear. The gear hydraulic motor operated, but the landing gear did not extend. After several seconds of gear motor operation, the circuit breaker for the gear motor popped. Subsequent attempts to extend the gear using both normal and emergency procedures were unsuccessful. A gear-up landing was executed.
Post-Accident Examination
After the accident, the aircraft was raised and the landing gear was successfully extended using the manual gear extension emergency hydraulic pump.
Maintenance Findings
Maintenance personnel discovered that a wire to the nose landing gear squat switch was chafed and grounded. This caused the system to be signaled for gear up at all times. Additionally, they stated that the pilot could not extend the gear using the backup hydraulic pump because the gear down solenoid had overheated during attempts to lower the gear and froze in the gear up position. After the solenoid cooled following the landing, they were able to manually lower the gear.