CEN26LA226

The pilot reported that upon entering the traffic pattern, he lowered the landing gear. He heard a loud “bang,” and only the main landing gear position indicator lights illuminated. The pilot contacted a friend on the ground to confirm if all three landing gear were down. The friend reported that the main landing gear were down. However, the nose gear was not down, and the nose gear door was closed. The pilot departed the traffic pattern and went through the emergency gear extension procedure. The nose landing gear position indicator light would still not illuminate. The pilot made the decision to perform a gear-up landing. The panels on the belly of the airplane were substantially damaged. A postaccident examination revealed that the pin on the nose gear brace assembly that engages with the cam on the nose landing gear door actuator shaft was not seated inside the cam, which rendered the nose landing gear inoperative. According to the airframe manufacturer, the pin is only in the slot when the landing gear door is retracted. The pin can disengage from the cam if there is a rigging issue and the rods for the door actuator are adjusted incorrectly or if the door actuator operating spring breaks. The mechanic who performed the last annual inspection reported that he utilized the approved airframe manufacturer maintenance manual for gear inspection and testing. According to the mechanic, the landing gear and gear door rigging were all within tolerance of the tensions and clearances called out in the maintenance manual, so no adjustments were made. He also confirmed that he examined the door actuator operating spring postaccident, and it was not broken.