What happened
During flight maneuvers, the pilot moved the landing gear handle to the down position but received an unsafe indication for the nose landing gear. The pilot attempted to troubleshoot the system and tried to lower the landing gear manually, but these efforts were unsuccessful.
The pilot subsequently performed a normal landing on the runway, and the aircraft initially began to roll out on all three landing gear. However, while decelerating through approximately 40 knots, the nose gear collapsed. The propeller struck the runway, causing the airplane to slide to a stop on its nose. There were no injuries reported.
The investigation
An examination of the nose landing gear revealed that a downlock actuator pin on the nose landing gear actuator had failed due to fatigue. This failure caused the pin to work partially out of its clevis half. The broken pin then contacted the actuator arm piston, which prevented the nose landing gear from traveling fully into the down and locked position.
Findings
- A downlock actuator pin on the nose landing gear actuator failed due to fatigue.
- The broken pin interfered with the actuator arm piston, preventing proper gear locking.
- A manufacturer's service bulletin regarding the inspection and replacement of these downlock pins had not been completed.